共查询到20条相似文献，搜索用时 15 毫秒
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Chandan Paul Provas Kumar Roy Vivekananda Mukherjee 《Optimal control applications & methods.》2023,44(2):480-507
Source of fossil fuel is impoverishing in the upcoming future. Renewable energy sources (RESs) are becoming challenging conventional energy substitutes in the present scenario. In this article, an attempt has been made to utilize RESs such as wind and solar energy with combined heat and power economic dispatch problems. The intention of this presentation is to minimize conflict objectives such as fuel cost accomplished with load demand along with transmission losses while satisfying all the constraints. A new optimization technique, namely a quasi-oppositionalbased whale optimization algorithm (QOWOA) is adopted to cope up with the non-linearities of the chosen systems. The proposed technique is tested on two different nonlinear realistic power systems to achieve the satisfactory performances. The superiority of the proposed QOWOA algorithm is judged by comparing it with some recently developed metaheuristic optimization techniques. 相似文献
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Preeti Ranjan Sahu Prakash Kumar Hota Sidhartha Panda 《Optimal control applications & methods.》2018,39(5):1802-1817
In this paper, the design of a fractional‐order (FO) multi‐input–single‐output (MISO)–type static synchronous series compensator (SSSC) is proposed with a goal to improve the power system stability using modified whale optimization algorithm (MWOA). The proposed MWOA achieves an appropriate balance between exploitation and exploration stages of the original whale optimization algorithm. The performance of MWOA is validated by employing the benchmark test functions and further contrasted with whale optimization algorithm and other heuristic algorithms like gravitational search algorithm, particle swarm optimization, differential evolution, and fast evolutionary programming algorithms to demonstrate its strength. The proposed FO MISO SSSC controller is optimized by the MWOA technique and tested under single‐machine infinite bus system and further extended to a multi‐machine framework. To demonstrate the superiority of MISO‐type SSSC controller, the results obtained from it are compared with particle swarm optimization and differential evolution–based conventional single‐input–single‐output structured SSSC controllers. The comparison of results of MWOA with that of other methods validates its superiority in the present context. 相似文献
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A novel unified approach to two‐degrees‐of‐freedom control is devised and applied to a classical chemical reactor model. The scheme is constructed from the optimal control point of view and along the lines of the Hamiltonian formalism for nonlinear processes. The proposed scheme optimizes both the feedforward and the feedback components of the control variable with respect to the same cost objective. The original Hamiltonian function governs the feedforward dynamics, and its derivatives are part of the gain for the feedback component. The optimal state trajectory is generated online, and is tracked by a combination of deterministic and stochastic optimal tools. The relevant numerical data to manipulate all stages come from a unique off‐line calculation, which provides design information for a whole family of related control problems. This is possible because a new set of PDEs (the variational equations) allow to recover the initial value of the costate variable, and the Hamilton equations can then be solved as an initial‐value problem. Perturbations from the optimal trajectory are abated through an optimal state estimator and a deterministic regulator with a generalized Riccati gain. Both gains are updated online, starting with initial values extracted from the solution to the variational equations. The control strategy is particularly useful in driving nonlinear processes from an equilibrium point to an arbitrary target in a finite‐horizon optimization context. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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This paper is concerned with the problems of reachable set estimation and synthesis for discrete‐time periodic systems under bounded peak disturbances. For the reachable set estimation problem, the lifting approach and the pseudo‐periodic Lyapunov function approach are utilized to determine the bounding ellipsoids for the reachable set. By using the lifting approach, the periodic system is transformed into several time‐invariant systems; then, the bounding ellipsoids are determined through the transformed time‐invariant systems. By applying the pseudo‐periodic Lyapunov function approach, the bounding ellipsoids are determined through the original periodic system directly. Genetic algorithm is adopted in the pseudo‐periodic Lyapunov function approach to search for the optimal value of the decision variables. Moreover, based on the reachable set estimation results, state‐feedback controllers are designed for manipulating the reachable set. Finally, numerical examples are presented to verify the effectiveness of the theoretical findings. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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El‐Kébir Boukas 《Optimal control applications & methods.》2010,31(4):335-349
This paper considers the class of continuous‐time singular linear Markovian jump systems with totally and partially known transition jump rates. The guaranteed cost control problem of this class of systems is tackled. New sufficient conditions for optimal guaranteed cost are developed. A design procedure for the guaranteed cost controller, which guarantees that the closed‐loop dynamics will be piecewise regular, impulse‐free and stochastically stable is proposed. It is shown that the addressed problem can be solved if the corresponding developed linear matrix inequalities (LMIs) with some constraints are feasible. A numerical example is employed to show the usefulness of the proposed results. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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Debasis Acharya;Dushmanta Kumar Das; 《Optimal control applications & methods.》2024,45(6):2651-2668
Artificial ventilators are vital respiratory support systems in the field of medical care, especially for patients in critical condition. It is crucial to make sure the ventilator keeps the intended airway pressure because variations might be harmful to the brain and lungs. Thus, achieving accurate pressure tracking is a primary objective in designing optimal controllers for pressure-controlled ventilators (PCVs). To address this need, a novel approach is proposed: a mixed integer tilted fractional order integral and integer order derivation controller tailored for PCV systems. The gains of different parameters of the proposed controller are optimized using an adaptive chaotic search fractional order class topper optimization algorithm, augmented with a Gaussian-based mutation operator. Moreover, the controller is designed to minimize oscillations in its output signal, thereby mitigating physical risks and reducing the size of actuators required. The efficacy of the optimized controller is further examined across various scenarios, including different lung resistances and compliances across different age groups of patients. Additionally, the impact of endotracheal tube resistance on air pressure is assessed as a potential disturbance in the PCV system. Through comprehensive testing, the proposed controller demonstrates superior performance in accurately tracking airway pressure to the desired levels. Across all evaluated cases, the proposed controller structure and accompanying algorithm outperform existing solutions. Notably, improvements are observed in system response time, overshoot, and settling time. This underscores the significance of employing advanced control strategies to enhancing the functionality and safety of PCV systems in medical settings. 相似文献
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Ricchetti A Burkhard PR Rodrigo N Gamulin Z Côte M Reverdin A Trussart C Landis BN Lacroix JS 《Head & neck》2004,26(5):464-469
BACKGROUND: The detection of the presence of cerebrospinal fluid (CSF) in nasal secretions contaminated with blood and mucus remains a challenging clinical problem. METHODS: A prospective study was conducted from November 1998 to February 2002, including 42 patients. Samples (250 microL) of nasal secretions were analyzed by two-dimensional electrophoresis (2-DE). Plasma, mucus, and CSF were identified by specific proteins markers corresponding to characteristic trains of spots. Intrathecal injection of fluorescein followed by the detection of fluorescein on endoscopic examination of the nasal cavities was considered a positive reference for CSF rhinorrhea. RESULTS: In all cases of positive fluorescein test, we unambiguously observed the presence of several specific CSF markers onto the 2-DE gels. Conversely, all negative fluorescein tests were associated with the absence of CSF-specific spots. CONCLUSIONS: Two-DE analyses of biologic fluids of nasal origin should be considered as a reliable diagnostic tool in case of suspicion of CSF leak. 相似文献
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Jenny A. Watson Keith Burling Patricia Fitzpatrick Elaine Kay John Kelly John M. Fitzpatrick Peter A. Dervan Amanda McCann 《BJU international》2009,103(5):694-697
OBJECTIVE
To examine urinary insulin‐like growth factor 2 (IGF‐2) levels in patient urine samples and determine the potential of IGF‐2 as a marker for the presence of urothelial carcinoma of the bladder (UCB).PATIENTS AND METHODS
The current gold standard for diagnosis of UCB is cystoscopy and cytological analysis. The identification of an accurate urine marker for UCB with the potential to replace unnecessary cystoscopy would benefit patients with UCB and others investigated after detecting haematuria. In the present study, we analysed 65 urine samples, and optimized an enzyme‐linked immunosorbent assay‐based approach to measure urinary levels of IGF‐2.RESULTS
Based on a threshold of 5.4 ng/mL, patients with UCB have significantly elevated levels of urinary IGF‐2 (P = 0.009) and this difference remained significant after adjustment for age and sex (P = 0.04). Sensitivity and specificity values of 80% and 52%, respectively, were determined for urinary IGF‐2 alone and when combined with nuclear matrix protein 22 (NMP22; an approved biomarker for detection of UCB). There was a positive correlation between urinary IGF‐2 levels and NMP22 levels in patient urine samples and the combined assay improved the detection of UCB (sensitivity 85% and specificity 52%).CONCLUSION
Substantiated evidence has identified IGF‐2 as a valuable marker for UCB. In addition, the novel observations of the present study have shown that aberrant levels of IGF‐2 occurring in the presence of UCB, can now be determined through a simple and inexpensive urine assay. 相似文献9.
BACKGROUND: A proportion of men with prostate cancer will progress to develop metastatic disease involving the lymph-nodes and bone. To identify novel candidates associated with metastatic progression, we compared the proteomic profiles of LNCaP (lymph-node metastatic, androgen-dependant) and PC-3 (bone metastatic, androgen-independent), human prostate cancer cells. METHODS: Two-dimensional polyacrylamide gel electrophoresis (2D-PAGE), followed by electrospray ionisation tandem mass spectrometry (ESI-MS/MS), was used to identify differentially expressed proteins. Western blotting was used to validate the identity of any candidates. Immunohistochemistry was used to assess tissue expression. RESULTS: 2D-PAGE followed by ESI-MS/MS analyses identified the expression of glutathione S-transferase-pi (GST-pi) and protein gene product 9.5 (PGP 9.5) in PC-3 cells, but absent expression in LNCaP cells. PGP 9.5 expression in PC-3 cells was confirmed by Western blotting, in addition to expression in DU145 cells. Analysis of cell conditioned media showed that PGP 9.5 was secreted. Sequencing of the PGP 9.5 gene promoter region in bisulfite modified DNA, suggested that the regulation of expression involves promoter hypermethylation. RT-PCR analysis for Chromogranin A (ChA) mRNA (a marker of neuroendocrine cells), showed expression in PC-3 and DU145 cells but was undetectable in LNCaP cells. Immunohistochemistry localised PGP 9.5 expression exclusively within neuroendocrine cells and nerve fibres. CONCLUSIONS: Our unexpected finding that the neuroendocrine cell markers PGP 9.5 and ChA are expressed by PC-3 and DU145 cells, suggests that these cells may have been derived from metastatic adenocarcinomas which had undergone neuroendocrine differentiation or alternatively the expression occurred ectopically as a result of cell culture. 相似文献
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Matthias May Maximilian Burger Wolfgang Otto Oliver W. Hakenberg Wolf F. Wieland Dieter May Ferdinand Hofstädter Stefanie Götz Nina Niessl Hans‐Martin Fritsche Kristina Birnkammer Christian Gilfrich Julia Peter Anjun Jain Stefan Koch Steffen Lebentrau Hubertus Riedmiller Wolfgang Rössler Stefan Denzinger Sabine Brookman‐May Sven Gunia 《BJU international》2013,112(4):E383-E390
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This paper addresses the design problem of fault‐tolerant H ∞ controller for linear systems with state quantization. By combining linear matrix inequality technique and indirect adaptive method, a new method is proposed to design a fault‐tolerant controller against actuator faults via quantized state feedback. The controller gains are updating according to the online estimation of eventual faults, which are dependent on the quantized state signals. Meanwhile, the proposed designs conditions with variable gains can be proved to be less conservative than those of the traditional controller with fixed gains. A numerical example is presented to illustrate the effectiveness of the proposed method. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
18.
Vik Khullar Gerard Amarenco Javier C. Angulo Mary Beth Blauwet Jameel Nazir Isaac A. Odeyemi Zalmai Hakimi 《Neurourology and urodynamics》2016,35(8):987-994
Aims
To assess patient‐reported outcomes (PROs) in patients with overactive bladder (OAB) receiving the novel β3‐adrenoceptor agonist mirabegron.Methods
Data from a randomised, double‐blind, controlled phase III trial in 1,987 patients aged ≥18 years with OAB symptoms for ≥3 months were analysed. Patients received placebo, mirabegron 50 or 100 mg/day, or tolterodine extended release (ER) 4 mg orally once daily for 12 weeks after a 2‐week placebo run‐in. Prespecified analysis of PROs (changes in OAB Questionnaire [OAB‐q], Patient Perception of Bladder Condition [PPBC], and Work Productivity and Activity Impairment: Specific Health Problem [WPAI‐SHP] instrument) in patients treated with mirabegron 50 mg/day, tolterodine ER 4 mg/day or placebo is reported. Post‐hoc analyses of OAB‐q, PPBC and the Treatment Satisfaction‐Visual Analogue Scale (TS‐VAS) in patients who were incontinent at baseline are also reported.Results
Significant improvements over placebo in OAB‐q coping and concern from baseline to final visit were observed with mirabegron 50 mg/day. No significant improvements in these parameters were observed with tolterodine ER 4 mg/day. Mirabegron 50 mg/day significantly increased the proportion of patients showing a PPBC improvement over placebo. Mirabegron 50 mg/day also produced greater improvements in WPAI‐SHP presenteeism and greater reductions in absenteeism and overall work impairment than placebo or tolterodine ER 4 mg/day. The impact of mirabegron 50 mg/day treatment on PROs in the incontinent population appears to be greater than that in the overall OAB population.Conclusions
At the approved dose of 50 mg/day, mirabegron significantly improves OAB patients' perception of disease and quality of life, independent of whether they are incontinent at baseline. Neurourol. Urodynam. 35:987–994, 2016. © 2015 The Authors. Neurourology and Urodynamics published by Wiley Periodicals, Inc. 相似文献19.
Hongxiang Wang Miao An Yidong Liu Kai Hu Yan Jin Shiran Xu Bin Chen Mujun Lu 《Andrology》2020,8(5):1064-1069
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Nan Zhang Bernd Schröppel Dongmei Chen Shuang Fu Kelly L. Hudkins Haojiang Zhang Barbara M. Murphy Randall S. Sung Jonathan S. Bromberg 《American journal of transplantation》2003,3(10):1230-1241
Adenoviral vectors are highly efficient for transferring genes to islets. However, the inflammatory and immune responses stimulated by adenovirus may be detrimental to islet survival. Given the role of chemokines and their receptors in inflammation, we analyzed their expression in isolated murine islets, in a murine beta cell line and in syngeneic islet grafts after adenovirus transduction (AdRSVLacZ). AdRSVLacZ transduction enhanced and induced the expression of a variety of chemokines. Transduced syngeneic transplanted islets showed significantly enhanced expression of multiple chemokines and receptors, including monocyte chemoattractant protein-1 (MCP-1), CC chemokine receptor 2 (CCR2) and regulated upon activation, normal T cell expressed and secreted (RANTES), compared with untransduced islet grafts. AdRSVLacZ-transduced islet grafts had significant mononuclear infiltrates, and in situ hybridization demonstrated intragraft expression of MCP-1, CCR2 and RANTES. Although adenovirus transduction did not impair in vitro insulin secretion, diabetes was reversed in only one of six recipients of a marginal mass of AdRSVLacZ-transduced islets, compared with six of six control recipients. In conclusion, multiple chemokines and chemokine receptors are expressed by murine islets constitutively and in response to adenovirus transduction. Adenovirus transduction impairs engraftment of marginal mass of transplanted islets. This is not because of direct vector toxicity of islet secretory capacity, but may be related to host innate immunity in response to adenovirus vector. 相似文献