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"optimal control theory"

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https://www.readbyqxmd.com/read/28507230/computational-design-of-treatment-strategies-for-proactive-therapy-on-atopic-dermatitis-using-optimal-control-theory
#1
Panayiotis Christodoulides, Yoshito Hirata, Elisa Domínguez-Hüttinger, Simon G Danby, Michael J Cork, Hywel C Williams, Kazuyuki Aihara, Reiko J Tanaka
Atopic dermatitis (AD) is a common chronic skin disease characterized by recurrent skin inflammation and a weak skin barrier, and is known to be a precursor to other allergic diseases such as asthma. AD affects up to 25% of children worldwide and the incidence continues to rise. There is still uncertainty about the optimal treatment strategy in terms of choice of treatment, potency, duration and frequency. This study aims to develop a computational method to design optimal treatment strategies for the clinically recommended 'proactive therapy' for AD...
June 28, 2017: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
https://www.readbyqxmd.com/read/28484801/optimal-control-of-vaccination-rate-in-an-epidemiological-model-of-clostridium-difficile-transmission
#2
Brittany Stephenson, Cristina Lanzas, Suzanne Lenhart, Judy Day
The spore-forming, gram-negative bacteria Clostridium difficile can cause severe intestinal illness. A striking increase in the number of cases of C. difficile infection (CDI) among hospitals has highlighted the need to better understand how to prevent the spread of CDI. In our paper, we modify and update a compartmental model of nosocomial C. difficile transmission to include vaccination. We then apply optimal control theory to determine the time-varying optimal vaccination rate that minimizes a combination of disease prevalence and spread in the hospital population as well as cost, in terms of time and money, associated with vaccination...
May 8, 2017: Journal of Mathematical Biology
https://www.readbyqxmd.com/read/28460243/optimal-control-design-of-preparation-pulses-for-contrast-optimization-in-mri
#3
Eric Van Reeth, Hélène Ratiney, Michael Tesch, Denis Grenier, Olivier Beuf, Steffen J Glaser, Dominique Sugny
This work investigates the use of MRI radio-frequency (RF) pulses designed within the framework of optimal control theory for image contrast optimization. The magnetization evolution is modeled with Bloch equations, which defines a dynamic system that can be controlled via the application of the Pontryagin Maximum Principle (PMP). This framework allows the computation of optimal RF pulses that bring the magnetization to a given state to obtain the desired contrast after acquisition. Creating contrast through the optimal manipulation of Bloch equations is a new way of handling contrast in MRI, which can explore the theoretical limits of the system...
April 21, 2017: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/28404782/signatures-of-optimal-control-in-pairs-of-schooling-zebrafish
#4
Andress Laan, Raul Gil de Sagredo, Gonzalo G de Polavieja
Animals moving in groups coordinate their motion to remain cohesive. A large amount of data and analysis of movement coordination has been obtained in several species, but we are lacking theoretical frameworks that can derive the form of coordination rules. Here, we examine whether optimal control theory can predict the rules underlying social interactions from first principles. We find that a control rule which is designed to minimize the time it would take a pair of schooling fish to form a cohesively moving unit correctly predicts the characteristics of social interactions in fish...
April 12, 2017: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/28301523/assessment-of-optimal-strategies-in-a-two-patch-dengue-transmission-model-with-seasonality
#5
Jung Eun Kim, Hyojung Lee, Chang Hyeong Lee, Sunmi Lee
Emerging and re-emerging dengue fever has posed serious problems to public health officials in many tropical and subtropical countries. Continuous traveling in seasonally varying areas makes it more difficult to control the spread of dengue fever. In this work, we consider a two-patch dengue model that can capture the movement of host individuals between and within patches using a residence-time matrix. A previous two-patch dengue model without seasonality is extended by adding host demographics and seasonal forcing in the transmission rates...
2017: PloS One
https://www.readbyqxmd.com/read/28222162/optimal-combinations-of-control-strategies-and-cost-effective-analysis-for-visceral-leishmaniasis-disease-transmission
#6
Santanu Biswas, Abhishek Subramanian, Ibrahim M ELMojtaba, Joydev Chattopadhyay, Ram Rup Sarkar
Visceral leishmaniasis (VL) is a deadly neglected tropical disease that poses a serious problem in various countries all over the world. Implementation of various intervention strategies fail in controlling the spread of this disease due to issues of parasite drug resistance and resistance of sandfly vectors to insecticide sprays. Due to this, policy makers need to develop novel strategies or resort to a combination of multiple intervention strategies to control the spread of the disease. To address this issue, we propose an extensive SIR-type model for anthroponotic visceral leishmaniasis transmission with seasonal fluctuations modeled in the form of periodic sandfly biting rate...
2017: PloS One
https://www.readbyqxmd.com/read/28186203/web-malware-spread-modelling-and-optimal-control-strategies
#7
Wanping Liu, Shouming Zhong
The popularity of the Web improves the growth of web threats. Formulating mathematical models for accurate prediction of malicious propagation over networks is of great importance. The aim of this paper is to understand the propagation mechanisms of web malware and the impact of human intervention on the spread of malicious hyperlinks. Considering the characteristics of web malware, a new differential epidemic model which extends the traditional SIR model by adding another delitescent compartment is proposed to address the spreading behavior of malicious links over networks...
February 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28166308/optimal-control-and-cost-effective-analysis-of-malaria-visceral-leishmaniasis-co-infection
#8
Folashade B Agusto, Ibrahim M ELmojtaba
In this paper, a deterministic model involving the transmission dynamics of malaria/visceral leishmaniasis co-infection is presented and studied. Optimal control theory is then applied to investigate the optimal strategies for curtailing the spread of the diseases using the use of personal protection, indoor residual spraying and culling of infected reservoirs as the system control variables. Various combination strategies were examined so as to investigate the impact of the controls on the spread of the disease...
2017: PloS One
https://www.readbyqxmd.com/read/28113535/discrete-time-nonzero-sum-games-for-multiplayer-using-policy-iteration-based-adaptive-dynamic-programming-algorithms
#9
Huaguang Zhang, He Jiang, Chaomin Luo, Geyang Xiao
In this paper, we investigate the nonzero-sum games for a class of discrete-time (DT) nonlinear systems by using a novel policy iteration (PI) adaptive dynamic programming (ADP) method. The main idea of our proposed PI scheme is to utilize the iterative ADP algorithm to obtain the iterative control policies, which not only ensure the system to achieve stability but also minimize the performance index function for each player. This paper integrates game theory, optimal control theory, and reinforcement learning technique to formulate and handle the DT nonzero-sum games for multiplayer...
October 3, 2016: IEEE Transactions on Cybernetics
https://www.readbyqxmd.com/read/28092262/vocal-development-in-a-waddington-landscape
#10
Yayoi Teramoto, Daniel Y Takahashi, Philip Holmes, Asif A Ghazanfar
Vocal development is the adaptive coordination of the vocal apparatus, muscles, the nervous system, and social interaction. Here, we use a quantitative framework based on optimal control theory and Waddington's landscape metaphor to provide an integrated view of this process. With a biomechanical model of the marmoset monkey vocal apparatus and behavioral developmental data, we show that only the combination of the developing vocal tract, vocal apparatus muscles and nervous system can fully account for the patterns of vocal development...
January 16, 2017: ELife
https://www.readbyqxmd.com/read/28088150/optimal-orientation-of-an-asymmetric-top-molecule-with-terahertz-pulses
#11
L H Coudert
Terahertz pulses effects are investigated in an asymmetric top C2v molecule using numerical simulations. The average value of the direction cosine ΦZx is computed solving the time dependent Schrödinger equation for several types of pulses. The H2S molecule taken as a test case is first subject to two short terahertz pulses with a duration smaller than 5 ps, an identical maximum value of the electric field of 2 MV/cm, but a different shape. The thermal average ⟨⟨ΦZx⟩⟩ is calculated for several temperatures, and non-periodic time variations are found even for the lowest temperature...
January 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/27989799/quantum-like-model-of-partially-directed-evolution
#12
REVIEW
Alexey V Melkikh, Andrei Khrennikov
The background of this study is that models of the evolution of living systems are based mainly on the evolution of replicators and cannot explain many of the properties of biological systems such as the existence of the sexes, molecular exaptation and others. The purpose of this study is to build a complete model of the evolution of organisms based on a combination of quantum-like models and models based on partial directivity of evolution. We also used optimal control theory for evolution modeling. We found that partial directivity of evolution is necessary for the explanation of the properties of an evolving system such as the stability of evolutionary strategies, aging and death, the presence of the sexes...
May 2017: Progress in Biophysics and Molecular Biology
https://www.readbyqxmd.com/read/27926436/to-work-or-not-to-work-neural-representation-of-cost-and-benefit-of-instrumental-action
#13
N B Kroemer, C Burrasch, L Hellrung
By definition, instrumental actions are performed in order to obtain certain goals. Nevertheless, the attainment of goals typically implies obstacles, and response vigor is known to reflect an integration of subjective benefit and cost. Whereas several brain regions have been associated with cost/benefit ratio decision-making, trial-by-trial fluctuations in motivation are not well understood. We review recent evidence supporting the motivational implications of signal fluctuations in the mesocorticolimbic system...
2016: Progress in Brain Research
https://www.readbyqxmd.com/read/27864095/optimization-of-an-in-vitro-chemotherapy-to-avoid-resistant-tumours
#14
Cécile Carrère
Chemotherapy use against solid tumours often results in the resistance of the cancer cells to the molecule used. In this paper, we will set up and analyse an ODE model for heterogeneous in vitro tumours, consisting of cells that are sensitive or resistant to a certain drug. We will then use this model to develop different protocols, that aim at reducing the tumour volume while preserving its heterogeneity. These drug administration schedules are determined through analysis of the system dynamics, and optimal control theory...
January 21, 2017: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/27725688/optimal-control-of-complex-atomic-quantum-systems
#15
S van Frank, M Bonneau, J Schmiedmayer, S Hild, C Gross, M Cheneau, I Bloch, T Pichler, A Negretti, T Calarco, S Montangero
Quantum technologies will ultimately require manipulating many-body quantum systems with high precision. Cold atom experiments represent a stepping stone in that direction: a high degree of control has been achieved on systems of increasing complexity. However, this control is still sub-optimal. In many scenarios, achieving a fast transformation is crucial to fight against decoherence and imperfection effects. Optimal control theory is believed to be the ideal candidate to bridge the gap between early stage proof-of-principle demonstrations and experimental protocols suitable for practical applications...
October 11, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27713655/quantifying-uncertainty-in-partially-specified-biological-models-how-can-optimal-control-theory-help-us
#16
M W Adamson, A Y Morozov, O A Kuzenkov
Mathematical models in biology are highly simplified representations of a complex underlying reality and there is always a high degree of uncertainty with regards to model function specification. This uncertainty becomes critical for models in which the use of different functions fitting the same dataset can yield substantially different predictions-a property known as structural sensitivity. Thus, even if the model is purely deterministic, then the uncertainty in the model functions carries through into uncertainty in model predictions, and new frameworks are required to tackle this fundamental problem...
September 2016: Proceedings. Mathematical, Physical, and Engineering Sciences
https://www.readbyqxmd.com/read/27176250/feedback-control-of-waiting-times
#17
Tobias Brandes, Clive Emary
Feedback loops are known as a versatile tool for controlling transport in small systems, which usually have large intrinsic fluctuations. Here we investigate the control of a temporal correlation function, the waiting-time distribution, under active and passive feedback conditions. We develop a general formalism and then specify to the simple unidirectional transport model, where we compare costs of open-loop and feedback control and use methods from optimal control theory to optimize waiting-time distributions...
April 2016: Physical Review. E
https://www.readbyqxmd.com/read/27143501/controlling-open-quantum-systems-tools-achievements-and-limitations
#18
Christiane P Koch
The advent of quantum devices, which exploit the two essential elements of quantum physics, coherence and entanglement, has sparked renewed interest in the control of open quantum systems. Successful implementations face the challenge of preserving relevant nonclassical features at the level of device operation. A major obstacle is decoherence, which is caused by interaction with the environment. Optimal control theory is a tool that can be used to identify control strategies in the presence of decoherence...
June 2, 2016: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/27131527/time-optimal-excitation-of-maximum-quantum-coherence-physical-limits-and-pulse-sequences
#19
S S Köcher, T Heydenreich, Y Zhang, G N M Reddy, S Caldarelli, H Yuan, S J Glaser
Here we study the optimum efficiency of the excitation of maximum quantum (MaxQ) coherence using analytical and numerical methods based on optimal control theory. The theoretical limit of the achievable MaxQ amplitude and the minimum time to achieve this limit are explored for a set of model systems consisting of up to five coupled spins. In addition to arbitrary pulse shapes, two simple pulse sequence families of practical interest are considered in the optimizations. Compared to conventional approaches, substantial gains were found both in terms of the achieved MaxQ amplitude and in pulse sequence durations...
April 28, 2016: Journal of Chemical Physics
https://www.readbyqxmd.com/read/26932466/input-estimation-for-drug-discovery-using-optimal-control-and-markov-chain-monte-carlo-approaches
#20
Magnus Trägårdh, Michael J Chappell, Andrea Ahnmark, Daniel Lindén, Neil D Evans, Peter Gennemark
Input estimation is employed in cases where it is desirable to recover the form of an input function which cannot be directly observed and for which there is no model for the generating process. In pharmacokinetic and pharmacodynamic modelling, input estimation in linear systems (deconvolution) is well established, while the nonlinear case is largely unexplored. In this paper, a rigorous definition of the input-estimation problem is given, and the choices involved in terms of modelling assumptions and estimation algorithms are discussed...
April 2016: Journal of Pharmacokinetics and Pharmacodynamics
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