Identification of nonlinear systems using hybrid functions

Most real systems have nonlinear behavior and thus model linearization may not produce an accurate representation of them. This paper presents a method based on hybrid functions to identify the parameters of nonlinear real systems. A hybrid function is a combination of two groups of orthogonal functions: piecewise orthogonal functions (e.g. Block-Pulse) and continuous orthogonal functions (e.g. Legendre polynomials). These functions are completed with an operational matrix of integration and a product matrix. Therefore, it is possible to convert nonlinear differential and integration equations into algebraic equations. After mathematical manipulation, the unknown linear and nonlinear parameters are identified. As an example, a mechanical system with single degree of freedom is simulated using the proposed method and the results are compared against those of an existing approach.<br /

Modeling and control of flatness in cold rolling mill using fuzzy petri nets

Today, having a good flatness control in steel industry is essential to ensure an overall product quality, productivity and successful processing. Flatness error, given as difference between measured strip flatness and target curve, can be minimized by modifying roll gap with various control functions. In most practical systems, knowing the definition of the model in order to have an acceptable control is essential. In this paper, a fuzzy Petri net method for modeling and control of flatness in cold rolling mill is developed. The method combines the concepts of Petri net and fuzzy control theories. It focuses on the fuzzy decision making problems of the fuzzy rule tree structures. The method is able to detect and recover possible errors that can occur in the fuzzy rule of the knowledge-based system. The method is implemented and simulated. The results show that its error is less than that of a PI conventional controller.<br /

Prognostic significance of endogenous adhesion/growth-regulatory lectins in lung cancer

Objective: To determine the expression of endogenous adhesion/growth-regulatory lectins and their binding sites using labeled tissue lectins as well as the binding profile of hyaluronic acid as an approach to define new prognostic markers. Methods: Sections of paraffin-embedded histological material of 481 lungs from lung tumor patients following radical lung excision processed by a routine immunohistochemical method (avidin-biotin labeling, DAB chromogen). Specific antibodies against galectins-1 and - 3 and the heparin-binding lectin were tested. Staining by labeled galectins and hyaluronic acid was similarly visualized by a routine protocol. After semiquantitative assessment of staining, the results were compared with the pT and pN stages and the histological type. Survival was calculated by univariate and multivariate methods. Results: Binding of galectin-1 and its expression tended to increase, whereas the parameters for galectin-3 decreased in advanced pT and pN stages at a statistically significant level. The number of positive cases was considerably smaller among the cases with small cell lung cancer than in the group with non-small-cell lung cancer, among which adenocarcinomas figured prominently with the exception of galectin-1 expression. Kaplan-Meier computations revealed that the survival rate of patients with galectin-3-binding or galectin-1-expressing tumors was significantly poorer than that of the negative cases. In the multivariate calculations of survival lymph node metastases ( p < 0.0001), histological type ( p = 0.003), galectin-3-binding capacity ( p = 0.01), galectin-3 expression ( p = 0.03) and pT status ( p = 0.003) proved to be independent prognostic factors, not correlated with the pN stage. Conclusion: The expression and the capacity to bind the adhesion/growth regulatory galectin-3 is defined as an unfavorable prognostic factor not correlated with the pTN stage. Copyright (C) 2005 S. Karger AG, Basel

The Prevalence of Goiter and Urinary Iodine Exertion in 7 – 10 year old

&lt;p&gt;&lt;strong&gt;Background and objectives&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Iodine deficiency was a public health problem in Iran before the start of iodine supplementation program in 1989. This study has been conducted in the framework of the national monitoring survey in 2001 to find the prevalence of goiter and urinary iodine levels in order to evaluate the effect of national supplementation program on the iodine status of school-aged children in the city of Qom.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;In a descriptive, cross-sectional study, 1200 schoolchildren, aged 7-10 years, were selected randomly from all regions of Qom, and the grade of goiter was determined in 600 boys and 600 girls according to WHO classification. Urinary iodine content was estimated using the digestion method in one tenth of the schoolchildren.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Goiter was observed in 26% of children (24.3% of girls and 27.7% of boys). The average urinary iodine level was 15.2 µg/dl. Urinary iodine levels higher than 10 μg/dl was measured in 71.7% and less than 5 µg/dl in 8.1% of children. Urinary iodine levels less than 2 μg/dl has not been observed in any of the cases. No significant difference was observed in prevalence of goiter and the urinary iodine level between males and females, and students in living in urban or rural areas.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusion&lt;/strong&gt;&lt;/p&gt;Comparison of these results with those of the year 1996 shows that prevalence of goiter has significantly decreased in these students. Also, it shows that in the city of Qom, the urinary iodine levels of schoolchildren fall in the standard range determined by WHO. This indicates that the iodine intake is adequate in the province of Qom. Therefore, this province can be considered as an “iodine deficiency-free” zon

Direct method for optimal power management in hybrid electric vehicles

Hybrid electric vehicles are powered by an electric system and an internal combustion engine. The components of a hybrid electric vehicle need to be coordinated in an optimal manner to deliver the desired performance. This paper presents an approach based on direct method for optimal power management in hybrid electric vehicles with inequality constraints. The approach consists of reducing the optimal control problem to a set of algebraic equations by approximating the state variable which is the energy of electric storage, and the control variable which is the power of fuel consumption. This approximation uses orthogonal functions with unknown coefficients. In addition, the inequality constraints are converted to equal constraints. The advantage of the developed method is that its computational complexity is less than that of dynamic and non-linear programming approaches. Also, to use dynamic or non-linear programming, the problem should be discretized resulting in the loss of optimization accuracy. The propsed method, on the other hand, does not require the discretization of the problem producing more accurate results. An example is solved to demonstrate the accuracy of the proposed approach. The results of Haar wavelets, and Chebyshev and Legendre polynomials are presented and discussed. &Acirc;&copy; 2011 The Korean Society of Automotive Engineers and Springer-Verlag Berlin Heidelberg

An MPC-based reference governor approach for offset-free control of constrained linear systems

This paper presents a model predictive control (MPC) based reference governor approach for control of constrained linear systems. A nominal closed-loop system is first designed to guarantee that, in the unconstrained case, asymptotic zero-error regulation for (piecewise) constant reference signals is achieved. Then, a couple of exogenous signals are added to the reference signal and to the control variable and their value is determined by formulating a MPC problem in order to guarantee that (i) when the state and control constraints are not active, the nominal closed-loop system is recovered, (ii) in transient conditions the constraints are always satisfied and the difference of the performances between the real and the nominal closed-loop systems is minimised, and (iii) when the reference signal is infeasible, the output is brought to the nearest feasible value. A simulation example is reported to witness the potentialities of the approach

Event-triggered fault detection for discrete-time linear multi-agent systems

This paper studies the design and development of event-triggered fault detection (FD) filters for discrete-time linear multi-agent systems. For each agent, an FD filter is designed that receives the output measurements from its neighboring agents whenever specific event conditions are satisfied. With our proposed methodology all agents collaborate with one another to detect the occurrence of faults in the team and each agent not only can detect its own fault but also is capable of detecting its neighbor's fault. The filter parameters and the event conditions are designed such that a mixed H?/H- performance index is guaranteed and it is shown that by using an event-triggered technique, the amount of data that is sent by each agent to its neighboring agents is dramatically decreased. Sufficient conditions for the solvability of the problem are obtained in terms of linear matrix inequalities (LMIs) where extended LMI characterizations are used to reduce the conservativeness of the multi-objective H?/H- problem. Simulation results corresponding to a team of autonomous unmanned underwater vehicles demonstrate and illustrate the effectiveness and capabilities of the proposed methodology. 2016 American Automatic Control Council (AACC).Scopu

Unknown primary detected by FDG-PET. A review of the present indications of FDG-PET in head and neck cancers.

To investigate the indications of 18F-2-fluoro-2-Deoxy-D-glucose (FDG) Positron Emission Tomography (PET) in head and neck cancer, the present study focuses on a case of cervical metastatic lymph node, which is not detected by the routine approach. It discusses the potential role of FDG-PET in the detection of unknown primary tumors, lymph node metastasis and post radiation follow-up, and demonstrates the implications of its findings through a few examples. Based on the literature in the field of head and neck oncology, the paper recommends the following uses for FDG-PET: 1. To guide biopsy or even local resection at the initial stage of examining the unknown primary lesions in case of high clinical suspicion 2. A whole body PET in high-risk patients may prevent unnecessary treatment and reduce the number of examinations 3. To monitor tumor response before full-dose irradiation so as not to delay the salvage surgery when applicable 4. To detect residual, recurrent or secondary neoplasm after definitive radiotherapy at least 4 months post-treatment 5. To revise the necessity of neck treatment in case of a negative PET, in the NO necks; and 6. In cases of clinical suspicion for laryngeal cancer recurrence and absence of objective findings before obtaining biopsy.Case ReportsJournal ArticleReviewinfo:eu-repo/semantics/publishe