scholarly journals A Novel Dissipativity-Based Control for Inexact Nonlinearity Cancellation Problems

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Giacomo Innocenti ◽  
Paolo Paoletti
Keyword(s):  
Control Strategy ◽  
Feedback Loop ◽  
Controller Design ◽  
Natural Control ◽  
Standard Methods ◽  
Approximation Quality ◽  
Linear Controller ◽  
Benchmark System ◽  
Global Linearization

When dealing with linear systems feedback interconnected with memoryless nonlinearities, a natural control strategy is making the overall dynamics linear at first and then designing a linear controller for the remaining linear dynamics. By canceling the original nonlinearity via a first feedback loop, global linearization can be achieved. However, when the controller is not capable of exactly canceling the nonlinearity, such control strategy may provide unsatisfactory performance or even induce instability. Here, the interplay between accuracy of nonlinearity approximation, quality of state estimation, and robustness of linear controller is investigated and explicit conditions for stability are derived. An alternative controller design based on such conditions is proposed and its effectiveness is compared with standard methods on a benchmark system.

Barrel temperature control for quality of thermoplastic polymers in the extrusion process

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
Murat Mayda
Keyword(s):  
Temperature Control ◽  
Control Strategy ◽  
Controller Design ◽  
Experimental Testing ◽  
Design Procedure ◽  
Extrusion Process ◽  
Operating Conditions ◽  
Single Screw Extruder ◽  
Performance Specifications

In this paper, the design procedure; modeling and controller design, testing are presented. Extensive tests have shown that the system reacts rapidly to changes in the operating conditions and effectively rejects disturbances due to unexpected changes in the quality of the material. This paper is the design and experimental testing of a feedback control system for the regulation of the volumetric flow in a polymer single screw extruder. Extruder temperature control is a challenging control problem. The problem becomes even more challenging when multiple barrel are included, such as in barrel temperature control for extruders. When characteristics of the system are examined, it becomes clear that a commonly used proportional plus compound plus derivative PID controller cannot meet such performance specifications for this kind of system. In order to achieve the required performance, a control strategy that utilizes techniques such as model predictive control, autotuning, and multiple parameter PID is formulated. This control strategy proves to be very effective in achieving the desired specifications.

Barrel temperature control for quality of thermoplastic polymers in the extrusion process

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Murat Mayda
Keyword(s):  
Temperature Control ◽  
Control Strategy ◽  
Controller Design ◽  
Experimental Testing ◽  
Design Procedure ◽  
Extrusion Process ◽  
Operating Conditions ◽  
Single Screw Extruder ◽  
Performance Specifications

In this paper, the design procedure; modeling and controller design, testing are presented. Extensive tests have shown that the system reacts rapidly to changes in the operating conditions and effectively rejects disturbances due to unexpected changes in the quality of the material. This paper is the design and experimental testing of a feedback control system for the regulation of the volumetric flow in a polymer single screw extruder. Extruder temperature control is a challenging control problem. The problem becomes even more challenging when multiple barrel are included, such as in barrel temperature control for extruders. When characteristics of the system are examined, it becomes clear that a commonly used proportional plus compound plus derivative PID controller cannot meet such performance specifications for this kind of system. In order to achieve the required performance, a control strategy that utilizes techniques such as model predictive control, autotuning, and multiple parameter PID is formulated. This control strategy proves to be very effective in achieving the desired specifications.

Barrel temperature control for quality of thermoplastic polymers in the extrusion process

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Murat Mayda
Keyword(s):  
Temperature Control ◽  
Control Strategy ◽  
Controller Design ◽  
Experimental Testing ◽  
Design Procedure ◽  
Extrusion Process ◽  
Operating Conditions ◽  
Single Screw Extruder ◽  
Performance Specifications

In this paper, the design procedure; modeling and controller design, testing are presented. Extensive tests have shown that the system reacts rapidly to changes in the operating conditions and effectively rejects disturbances due to unexpected changes in the quality of the material. This paper is the design and experimental testing of a feedback control system for the regulation of the volumetric flow in a polymer single screw extruder. Extruder temperature control is a challenging control problem. The problem becomes even more challenging when multiple barrel are included, such as in barrel temperature control for extruders. When characteristics of the system are examined, it becomes clear that a commonly used proportional plus compound plus derivative PID controller cannot meet such performance specifications for this kind of system. In order to achieve the required performance, a control strategy that utilizes techniques such as model predictive control, autotuning, and multiple parameter PID is formulated. This control strategy proves to be very effective in achieving the desired specifications.

Flouride and Nitrate Status of Some Ground Waters in Chittor District of Rajasthan State (India)

2018 ◽  
Vol 6 (9) ◽  
pp. 119
Author(s):  
Trapti Sharma ◽  
R. P. Nagar ◽  
R. C. Gaur ◽  
Pooja Gupta ◽  
Charanjit Kaur
Keyword(s):  
Point Of View ◽  
World Health ◽  
Indian Council ◽  
Standard Methods ◽  
Ground Waters ◽  
Drinking Waters ◽  
Health Organization ◽  
Research World ◽  
Drinking Purpose

In Rajasthan state the ground waters of some areas like Ramganj-mandi, Morak, Barmer, Jaisalmer, Chittor and Udaipur etc. are susceptible from drinking point of view.To test the quality of groundwater in Chittor district 14, ground water samples were collected from various places and analyzed for pH, E.C., Fluoride and Nitrate parameters by standard methods (A.P.H. A., Washington, USA, 1995). The study revealed that none of the ground waters was found suitable completely from drinking point of view. Some are having electrical conductivity > 1.4 dS/m, some are having pH >8.5, some area having fluoride >1.5 ppm and some are having nitrate>45 ppm. These are the limits of various parameters permitted by various International authorities like Bureau of Indian Standard, Indian Council of Medical Research,world health Organization etc. for drinking waters. So, it is recommended to the residents of above areas to use water for drinking purpose only after reverse osmosis or adopting suitable method of removing excess of Fluoride and Nitrate for drinking water to avoid unwanted pathogenic diseases harmful for human health.

A Human/Computer Learning Network to Improve Biodiversity Conservation and Research

AI Magazine ◽  
2012 ◽  
Vol 34 (1) ◽  
pp. 10 ◽  
Author(s):  
Steve Kelling ◽  
Jeff Gerbracht ◽  
Daniel Fink ◽  
Carl Lagoze ◽  
Weng-Keen Wong ◽  
...  
Keyword(s):  
Artificial Intelligence ◽  
Feedback Loop ◽  
Human Computation ◽  
Computational Power ◽  
Learning Networks ◽  
Learning Network ◽  
Computer Learning ◽  
The Individual ◽  
Citizen Science Project

In this paper we describe eBird, a citizen-science project that takes advantage of the human observational capacity to identify birds to species, which is then used to accurately represent patterns of bird occurrences across broad spatial and temporal extents. eBird employs artificial intelligence techniques such as machine learning to improve data quality by taking advantage of the synergies between human computation and mechanical computation. We call this a Human-Computer Learning Network, whose core is an active learning feedback loop between humans and machines that dramatically improves the quality of both, and thereby continually improves the effectiveness of the network as a whole. In this paper we explore how Human-Computer Learning Networks can leverage the contributions of a broad recruitment of human observers and processes their contributed data with Artificial Intelligence algorithms leading to a computational power that far exceeds the sum of the individual parts.

Performance Improvement of SVPWM-Based Three-Phase Grid-Connected Inverters

2013 ◽  
Vol 732-733 ◽  
pp. 1261-1264
Author(s):  
Zhi Lei Yao ◽  
Lan Xiao ◽  
Jing Xu
Keyword(s):  
Dynamic Response ◽  
Control Strategy ◽  
Pulse Width Modulation ◽  
Control Method ◽  
Grid Current ◽  
Current Controller ◽  
Three Phase ◽  
Reference Grid ◽  
Grid Connected Inverter

An improved control strategy for three-phase grid-connected inverters with space vector pulse width modulation (SVPWM) is proposed. When the grid current contains harmonics, the d-and q-axes grid currents is interacted in the traditional control method, and the waveform quality of the grid current is poor. As the reference output voltage cannot directly reflect the change of the reference grid current with the traditional control strategy, the dynamic response of the grid-connected inverter is slow. In order to solve the aforementioned problems, the d-and q-axes grid currents in the decoupled components of the grid current controller are substituted by the d-and q-axes reference grid currents, respectively. The operating principles of the traditional and proposed control methods are illustrated. Experimental results show that the grid-connected inverter with the improved control strategy has high waveform quality of the grid current and fast dynamic response.

scholarly journals Rate-control vs rhythm-control of atrial fibrillation in elderly patients. From new, age-oriented outcomes to a more complex management strategy

2018 ◽  
Vol 88 (2) ◽  
Author(s):  
Stefano Fumagalli ◽  
Serena Boni ◽  
Simone Pupo ◽  
Marta Migliorini ◽  
Irene Marozzi ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Control Strategy ◽  
Rate Control ◽  
The Elderly ◽  
Epidemiological Studies ◽  
Rhythm Control ◽  
Aged Patients ◽  
Aged People ◽  
Arrhythmia Management

Atrial fibrillation (AF) is the most frequent arrhythmia in elderly people. Findings derived from clinical trials seem to demonstrate that a rate-control strategy of AF in aged patients improves prognosis if compared to a rhythm-control one. However, epidemiological studies concordantly show that the arrhythmia is associated to increased hospitalization and mortality rates. In last years, the proportion of patients admitted to hospital for AF has progressively increased; this trend is observed in subjects >75 and >85 years, while no change was found in younger cohorts. Importantly, in aged individuals, probably because of the loss of atrial activity, the increase of heart rate and the irregularity of RR intervals, AF begins a vicious cycle, leading from heart failure, through the compromise of functional and neurocognitive status, to overt disability, dementia and increased mortality. Evidence specifically aimed at clarifying the effects of arrhythmia management on outcomes characteristic of aged people is completely lacking. In the elderly, the question regarding the effects of a rate- or a rhythm-control strategy of AF should be considered as an aspect of a more complex strategy, addressed to reduce disability and hospitalizations, and to improve quality of life and survival.

scholarly journals METHOD DECISION FOR DETERMINING SPECIFIC MICROORGANISMS IN PHARMACEUTICAL PRODUCTS: AN OVERVIEW

2020 ◽  
Author(s):  
Gökhan CENGİZ ◽  
Evren ALGIN YAPAR
Keyword(s):  
Quality Control ◽  
Peer Review ◽  
Pathogenic Bacteria ◽  
Microbiological Quality ◽  
Pharmaceutical Products ◽  
Eye Drops ◽  
Control Analysis ◽  
Standard Methods ◽  
Quality Control Analysis

In the direction of microbiological quality control analysis in pharmaceutical products, determining the microbiological load of the product at the end-use stage is very important for human health. Quality control parameters in pharmaceutical products vary according to the structure of the type of product and administration route. In this context, according to the pharmacopoeias, parenteral products and eye drops are classified as sterile products and the other group of pharmaceuticals are classified as non-sterile products. However, non-sterile pharmaceuticals also must have a certain microbiological quality. For this reason, the pharmaceuticals should have a certain microbiological load and should not contain defined microorganisms specified to its type. Since the control of the microbiological quality of the products is important for safety, it should be determined by quality control analysis. In this study, standard methods used to detect specific microorganism in pharmaceutical products were compared. Application steps in standard methods and identification tests of specific microorganisms were examined. In addition, studies that are alternative to standard methods were evaluated. Peer Review History: Received: 5 September 2020; Revised: 20 October; Accepted: 28 October, Available online: 15 November 2020 UJPR follows the most transparent and toughest ‘Advanced OPEN peer review’ system. The identity of the authors and, reviewers will be known to each other. This transparent process will help to eradicate any possible malicious/purposeful interference by any person (publishing staff, reviewer, editor, author, etc) during peer review. As a result of this unique system, all reviewers will get their due recognition and respect, once their names are published in the papers. We expect that, by publishing peer review reports with published papers, will be helpful to many authors for drafting their article according to the specifications. Auhors will remove any error of their article and they will improve their article(s) according to the previous reports displayed with published article(s). The main purpose of it is ‘to improve the quality of a candidate manuscript’. Our reviewers check the ‘strength and weakness of a manuscript honestly’. There will increase in the perfection, and transparency. Received file Average Peer review marks at initial stage: 6.0/10 Average Peer review marks at publication stage: 8.0/10 Reviewer(s) detail: Dr. Mujde Eryilmaz, Ankara University,Turkey, [email protected] Dr. Rawaa Souhil Al-Kayali, Aleppo University, Syria, [email protected]   Comments of reviewer(s): Similar Articles: CHEMICAL COMPOSITION AND ANTIMICROBIAL ACTIVITY OF THE ESSENTIAL OILS OF FOUR VARIETIES OF LIPPIA MULTIFLORA IN BENIN ANTIMICROBIAL ACTIVITIES FOR HADHRAMI HONEY ON GROWTH OF SOME PATHOGENIC BACTERIA

scholarly journals Mixture Based Outlier Filtration

10.14311/816 ◽  
2006 ◽  
Vol 46 (2) ◽  
Author(s):  
P. Pecherková ◽  
I. Nagy
Keyword(s):  
Model Identification ◽  
Real Data ◽  
Control Algorithms ◽  
Linear Quadratic ◽  
Process Data ◽  
Linear Quadratic Gaussian ◽  
Standard Methods ◽  
Two Component ◽  
Reconstruction Filter

Success/failure of adaptive control algorithms – especially those designed using the Linear Quadratic Gaussian criterion – depends on the quality of the process data used for model identification. One of the most harmful types of process data corruptions are outliers, i.e. ‘wrong data’ lying far away from the range of real data. The presence of outliers in the data negatively affects an estimation of the dynamics of the system. This effect is magnified when the outliers are grouped into blocks. In this paper, we propose an algorithm for outlier detection and removal. It is based on modelling the corrupted data by a two-component probabilistic mixture. The first component of the mixture models uncorrupted process data, while the second models outliers. When the outlier component is detected to be active, a prediction from the uncorrupted data component is computed and used as a reconstruction of the observed data. The resulting reconstruction filter is compared to standard methods on simulated and real data. The filter exhibits excellent properties, especially in the case of blocks of outliers. 

A Photorealistic Predictive Display

2004 ◽  
Vol 13 (1) ◽  
pp. 22-43 ◽  
Author(s):  
Tim Burkert ◽  
Jan Leupold ◽  
Georg Passig
Keyword(s):  
Time Delays ◽  
Feedback Loop ◽  
Communication Channel ◽  
Graphics Hardware ◽  
Model Data ◽  
Predictive Display ◽  
Teleoperation System ◽  
Processing Techniques ◽  
Texture Extraction

The quality of a teleoperation system is decreased by time delays in the communication channel. Delays as low as a few hundred milliseconds between commanding an action and getting the visual feedback reduce the operator's performance. Predictive displays have proven their suitability to compensate for these delays, but at the expense of image quality when using computer-generated images. A photorealistic predictive display is presented that closes the feedback loop locally at the operator's side of a telepresence system. Photorealism is achieved using delayed camera images for texturing the predicted scene. Consumer graphics hardware is not only used for rendering but also for hardware-accelerated texture extraction. To allow concurrent access to model data, a multibuffer model structure is presented. A model of the teleoperator's environment is automatically acquired and updated by image processing techniques using a stereo camera as the only sensor.

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