scholarly journals Duality in the optimal control for damped hyperbolic systems with positive control

2003 ◽  
Vol 2003 (27) ◽  
pp. 1703-1714
Author(s):  
Mi Jin Lee ◽  
Jong Yeoul Park ◽  
Young Chel Kwon
Keyword(s):  
Optimal Control ◽  
Duality Theory ◽  
Duality Theorem ◽  
Hyperbolic Equations ◽  
Hyperbolic Systems ◽  
Positive Control ◽  
Cost Functions ◽  
Convex Cost ◽  
Cost Functionals ◽  
Positive Controls

We study the duality theory for damped hyperbolic equations. These systems have positive controls and convex cost functionals. Our main results lie in the application of duality theorem, that is,inf J=sup K, on various cost functions.

scholarly journals Duality in the optimal control of hyperbolic equations with positive controls

2000 ◽  
Vol 23 (3) ◽  
pp. 181-188
Author(s):  
Jong Yeoul Park ◽  
Mi Jin Lee
Keyword(s):  
Optimal Control ◽  
Control Systems ◽  
Distributed Control ◽  
Duality Theory ◽  
Hyperbolic Equations ◽  
Positive Control ◽  
Distributed Control Systems ◽  
Convex Cost ◽  
Cost Functionals ◽  
Positive Controls

We study the duality theory for hyperbolic equations. Also, we consider distributed control systems with positive control and convex cost functionals.

scholarly journals Existence of solutions and optimal control problems for hyperbolic hemivariational inequalities

2005 ◽  
Vol 47 (1) ◽  
pp. 51-63 ◽  
Author(s):  
Jong Yeoul Parks ◽  
Sun Hye Park
Keyword(s):  
Optimal Control ◽  
Optimal Control Problems ◽  
Existence Of Solutions ◽  
Hemivariational Inequalities ◽  
Control Problems ◽  
Convex Cost ◽  
Cost Functionals

AbstractIn this paper we prove the existence of solutions for hyperbolic hemivariational inequalities and then investigate optimal control problems for some convex cost functionals.

scholarly journals An Optimal Control Problem by a Hybrid System of Hyperbolic and Ordinary Differential Equations

Games ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 23
Author(s):  
Alexander Arguchintsev ◽  
Vasilisa Poplevko
Keyword(s):  
Optimal Control ◽  
Differential Equations ◽  
Optimal Control Problem ◽  
Control Problem ◽  
Ordinary Differential Equations ◽  
Hyperbolic Equations ◽  
Control Methods ◽  
The Right ◽  
The Cost ◽  
Optimal Control Methods

This paper deals with an optimal control problem for a linear system of first-order hyperbolic equations with a function on the right-hand side determined from controlled bilinear ordinary differential equations. These ordinary differential equations are linear with respect to state functions with controlled coefficients. Such problems arise in the simulation of some processes of chemical technology and population dynamics. Normally, general optimal control methods are used for these problems because of bilinear ordinary differential equations. In this paper, the problem is reduced to an optimal control problem for a system of ordinary differential equations. The reduction is based on non-classic exact increment formulas for the cost-functional. This treatment allows to use a number of efficient optimal control methods for the problem. An example illustrates the approach.

Solutions and gels containing a sugarcane-derived cystatin (CaneCPI-5) reduce enamel and dentin erosion in vitro

2021 ◽  
Author(s):  
Lethycia Almeida Santos ◽  
Tatiana Martini ◽  
João Victor Frazão Câmara ◽  
Fabiana Navas Reis ◽  
Adriana de Cássia Ortiz ◽  
...  
Keyword(s):  
Artificial Saliva ◽  
Dental Erosion ◽  
Positive Control ◽  
New Approach ◽  
Enamel Erosion ◽  
Ph Cycling ◽  
Bovine Enamel ◽  
Dentin Erosion ◽  
Positive Controls

The effect of solutions and gels containing a sugarcane-derived cystatin (CaneCPI-5) on the protection against enamel and dentin erosion in vitro was evaluated. Bovine enamel and dentin specimens were divided into two groups (n=135 and 153/group for enamel and dentin, respectively) that were treated with solutions or chitosan gels containing 0.1 or 0.25 mg/ml CaneCPI-5. The positive controls for solutions and gels were Elmex Erosion Protection™ solution and NaF gel (12,300 ppm F), respectively. Deionized water and chitosan gel served as controls, respectively. The solutions were first applied on the specimens for 1 min and the gels for 4 min. Stimulated saliva was collected from 3 donors and used to form a 2 h acquired pellicle on the specimens. Then, the specimens were submitted to an erosive pH cycling protocol 4 times/day for 7 days (0.1% citric acid pH 2.5/90s, artificial saliva/2h, artificial saliva overnight). The solutions and gels were applied again during pH cycling, 2 times/day for 1 min and 4 min, respectively, after the first and last erosive challenges. Enamel and dentin losses (µm) were assessed by contact profilometry. Data were analyzed by 2-way ANOVA and Tukey´s test (p <0.05). All the treatments significantly reduced enamel and dentin loss in comparison with controls. Both CaneCPI-5 concentrations had a similar protective effect against enamel erosion, but only the higher concentration was as effective against dentin erosion as the positive control. Regarding the vehicles, only the 0.1 mg/ml gel performed worse than the positive control for dentin. CaneCPI-5 reduced enamel and dentin erosion to a similar extent as the fluoride-containing vehicles. However, dentin requires higher CaneCPI-5 concentrations, in the case of gels. Solutions or gels containing CaneCPI-5 might be a new approach to protect against dental erosion.

Improved Method for the ASTM Platelet and Leukocyte Assay: Use of Minimal Heparinization in a Screening Test for Hemocompatibility of Blood-Contacting Medical Devices

2018 ◽  
Vol 13 (1) ◽  
Author(s):  
Tim Schatz ◽  
Sarah Howard ◽  
Deanna Porter ◽  
Kent Grove ◽  
Mark E. Smith ◽  
...  
Keyword(s):  
Medical Devices ◽  
High Density Polyethylene ◽  
Complete Blood Count ◽  
Clinical History ◽  
Positive Control ◽  
Final Concentration ◽  
Surface Adhesion ◽  
Improved Method ◽  
Robust Response ◽  
Positive Controls

Most blood-contacting medical devices must be assessed for potential thrombogenicity prior to regulatory approval. A common assay for screening and qualifying devices involves monitoring the reduction of platelet and leukocyte (P&L) counts in whole blood exposed to the device. We have validated an improved method for assessing a device's effect on platelet activation and surface adhesion, offering significant improvement over the current ASTM F2888-13 method, which uses blood fully anticoagulated by acidified citrate (known to significantly inhibit platelet responsiveness). Our method uses minimal heparinization (final concentration 1 IU/mL) to optimize the response to commonly used control materials: latex, black rubber, and high-density polyethylene (HDPE). We also have shown the assay's capacity to appropriately assess a legally marketed comparator device (LMCD) with a documented clinical history. The test materials were prepared for incubation and allowed to remain in contact with the citrated or heparinized blood for ∼1 h at 37 °C. A complete blood count was performed prior to exposure, and at the end of the incubation period, reductions in P&L counts were recorded. Results from citrate-anticoagulated assay showed only a marginal response to the positive control, black rubber. Using heparinized blood, the assay generated a robust response to the positive controls, the “intermediate scoring” controls, and also assessed a legally marketed and approved device as clearly nonthrombogenic. This modification adds robustness and sensitivity to this quick and inexpensive thrombogenicity assay and should be incorporated into the next ASTM standards.

scholarly journals Reduction in the Number of Animals and the Evaluation Period for the Positive Control Group in Tg.rasH2 Short-Term Carcinogenicity Studies

2012 ◽  
Vol 31 (5) ◽  
pp. 423-429 ◽  
Author(s):  
Sudhir A. Shah ◽  
Madhav. G. Paranjpe ◽  
Philip I. Atkins ◽  
Eias A. Zahalka
Keyword(s):  
Positive Control ◽  
Lung Tumors ◽  
Control Group ◽  
Short Term ◽  
Evaluation Period ◽  
Target Organs ◽  
The Us ◽  
Assessment Committee ◽  
Robust Response ◽  
Positive Controls

The lack of a clear guidance on the adequate number of animals used for positive controls in the short-term (26-weeks) transgenic mouse carcinogenicity studies has resulted in the use of high number of animals. In our earlier Tg.rasH2 studies, 25 mice/sex were used in the urethane-positive control dose groups that were sacrificed by 18 weeks. Based on a robust response, several of our protocols for Tg.rasH2 studies with 15 mice/sex and terminal sacrifice at 17 ± 1 weeks were submitted and accepted by the Carcinogenicity Assessment Committee of the US Food and Drug Administration since we demonstrated close to 100% response for the development of lung and splenic tumors (target organs) in 500 mice/sex. These 500 mice/sex included 17 groups of 25 mice/sex and 5 groups of 15 mice/sex.  The objective of this investigation was to determine whether the number of animals can be further reduced along with the shortened duration of exposure to urethane. Accordingly, 10 Tg.rasH2 mice/sex/group were administered a total of 3 intraperitoneal (IP) injections of urethane (1000 mg/kg per day) on study days 1, 3, and 5, and the presence of tumors in the lungs and spleen was evaluated after 8, 10, 12, 14, or 16 weeks. Our results demonstrate that 100% of the mice at 8 weeks had developed lung tumors, whereas close to 100% of the mice at 14 weeks had developed splenic tumors. Based on the development of lung tumors alone in 100% of the mice, we recommend that 10 mice/sex are sufficient and that these mice can also be sacrificed as early as 10 ± 1 weeks following the administration of urethane.

High-order relaxation approaches for adjoint-based optimal control problems governed by nonlinear hyperbolic systems of conservation laws

2016 ◽  
Vol 24 (1) ◽  
Author(s):  
Elimboto M. Yohana ◽  
Mapundi K. Banda
Keyword(s):  
Optimal Control ◽  
Conservation Laws ◽  
Optimal Control Problems ◽  
Initial Conditions ◽  
Hyperbolic Systems ◽  
Control Problems ◽  
Computational Investigation ◽  
Backward Problem ◽  
Systems Of Conservation Laws ◽  
The Cost

AbstractA computational investigation of optimal control problems which are constrained by hyperbolic systems of conservation laws is presented. The general framework is to employ the adjoint-based optimization to minimize the cost functional of matching-type between the optimal and the target solution. Extension of the numerical schemes to second-order accuracy for systems for the forward and backward problem are applied. In addition a comparative study of two relaxation approaches as solvers for hyperbolic systems is undertaken. In particular optimal control of the 1-D Riemann problem of Euler equations of gas dynamics is studied. The initial values are used as control parameters. The numerical flow obtained by optimal initial conditions matches accurately with observations.

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