scholarly journals Common foundations of optimal control across the sciences: evidence of a free lunch

2017 ◽  
Vol 375 (2088) ◽  
pp. 20160210 ◽  
Author(s):  
Benjamin Russell ◽  
Herschel Rabitz
Keyword(s):  
Evolutionary Biology ◽  
Quantum Control ◽  
Mathematical Framework ◽  
Optimal Controls ◽  
Control Variables ◽  
Common Control ◽  
Algorithmic Search ◽  
Set Up ◽  
Open Question ◽  
Control Landscape

A common goal in the sciences is optimization of an objective function by selecting control variables such that a desired outcome is achieved. This scenario can be expressed in terms of a control landscape of an objective considered as a function of the control variables. At the most basic level, it is known that the vast majority of quantum control landscapes possess no traps, whose presence would hinder reaching the objective. This paper reviews and extends the quantum control landscape assessment, presenting evidence that the same highly favourable landscape features exist in many other domains of science. The implications of this broader evidence are discussed. Specifically, control landscape examples from quantum mechanics, chemistry and evolutionary biology are presented. Despite the obvious differences, commonalities between these areas are highlighted within a unified mathematical framework. This mathematical framework is driven by the wide-ranging experimental evidence on the ease of finding optimal controls (in terms of the required algorithmic search effort beyond the laboratory set-up overhead). The full scope and implications of this observed common control behaviour pose an open question for assessment in further work. This article is part of the themed issue ‘Horizons of cybernetical physics’.

scholarly journals Experimental exploration over a quantum control landscape through nuclear magnetic resonance

2014 ◽  
Vol 89 (3) ◽  
Author(s):  
Qiuyang Sun ◽  
István Pelczer ◽  
Gregory Riviello ◽  
Re-Bing Wu ◽  
Herschel Rabitz
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Quantum Control ◽  
Control Landscape ◽  
Nuclear Magnetic

scholarly journals Sex, amitosis, and evolvability in the ciliate Tetrahymena thermophila

2021 ◽  
Author(s):  
Jason A Tarkington ◽  
Hao Zhang ◽  
Ricardo Azevedo ◽  
Rebecca Zufall
Keyword(s):  
Genetic Variation ◽  
Experimental Evolution ◽  
Evolutionary Biology ◽  
Genetic Architecture ◽  
Nuclear Division ◽  
Tetrahymena Thermophila ◽  
Laboratory Populations ◽  
Evolutionary Success ◽  
Sexual Progeny ◽  
Open Question

Understanding the mechanisms that generate genetic variation, and thus contribute to the process of adaptation, is a major goal of evolutionary biology. Mutation and genetic exchange have been well studied as mechanisms to generate genetic variation. However, there are additional processes that may also generate substantial genetic variation in some populations and the extent to which these variation generating mechanisms are themselves shaped by natural selection is still an open question. Tetrahymena thermophila is a ciliate with an unusual mechanism of nuclear division, called amitosis, which can generate genetic variation among the asexual descendants of a newly produced sexual progeny. We hypothesize that amitosis thus increases the evolvability of newly produced sexual progeny relative to species that undergo mitosis. To test this hypothesis, we used experimental evolution and simulations to compare the rate of adaptation in T. thermophila populations founded by a single sexual progeny to parental populations that had not had sex in many generations. The populations founded by a sexual progeny adapted more quickly than parental populations in both laboratory populations and simulated populations. This suggests that the additional genetic variation generated by amitosis of a heterozygote can increase the rate of adaptation following sex and may help explain the evolutionary success of the unusual genetic architecture of Tetrahymena and ciliates more generally.

scholarly journals The New Set Up of Local Performance Indices into WaterNetGen and Application to Santarém’s Network

2020 ◽  
Vol 2 (1) ◽  
pp. 18 ◽  
Author(s):  
Marco Amos Bonora ◽  
Fabio Caldarola ◽  
Mario Maiolo ◽  
Joao Muranho ◽  
Joaquim Sousa
Keyword(s):  
Water Distribution ◽  
Global Analysis ◽  
Distribution Network ◽  
Water Distribution Network ◽  
Mathematical Framework ◽  
Water Networks ◽  
Performance Indices ◽  
Set Up ◽  
Pressure Driven Analysis

A new set of local performance indices has recently been introduced within a mathematical framework specifically designed to promote a local–global analysis of water networks. Successively, some local indices were also set up and implemented on WaterNetGen to better exploit their potential. In this paper, after a very brief overview of tools and main notations, Santarém’s (Portugal) water distribution network (WDN) is examined, applying to it the mentioned set of local indices, as a new real case study. The paper also focuses on the Hypotesis required to assess these indices in a pressure driven analysis (PDA) approach, analyzing and discussing the results obtained from such a simulation.

scholarly journals Exploring quantum control landscape structure

2013 ◽  
Vol 88 (3) ◽  
Author(s):  
Arun Nanduri ◽  
Ashley Donovan ◽  
Tak-San Ho ◽  
Herschel Rabitz
Keyword(s):  
Landscape Structure ◽  
Quantum Control ◽  
Control Landscape

scholarly journals Critical Points of the Optimal Quantum Control Landscape: A Propagator Approach

2012 ◽  
Vol 118 (1) ◽  
pp. 49-56 ◽  
Author(s):  
Tak-San Ho ◽  
Herschel Rabitz ◽  
Gabriel Turinici
Keyword(s):  
Critical Points ◽  
Quantum Control ◽  
Control Landscape

Glider fuselage-wing junction optimization using CFD and RBF mesh morphing

2016 ◽  
Vol 88 (6) ◽  
pp. 740-752 ◽  
Author(s):  
Marco Evangelos Biancolini ◽  
Emiliano Costa ◽  
Ubaldo Cella ◽  
Corrado Groth ◽  
Gregor Veble ◽  
...  
Keyword(s):  
High Performance ◽  
Optimization Procedure ◽  
Local Geometry ◽  
Mathematical Framework ◽  
Aerodynamic Efficiency ◽  
Content Type ◽  
Mesh Morphing ◽  
Design Variables ◽  
Optimization Study ◽  
Set Up

Purpose The present paper aims to address the description of a numerical optimization procedure, based on mesh morphing, and its application for the improvement of the aerodynamic performance of an industrial glider which suffers of a large separation occurring in the wing–fuselage junction region at high incidence angles. Design/methodology/approach Shape variations were applied to the baseline configuration through a mesh morphing technique founded on the mathematical framework of radial basis functions (RBF). The aerodynamic solutions were obtained coupling an RANS code with the mesh morphing tool RBF Morph™. Two shape modifiers were set up to generate a parametric numerical model. An optimization procedure, based on a design of experiment sampling, was set up implementing the fully automated workflow within a high performance computing (HPC) environment. The optimal candidates maximizing the aerodynamic efficiency were identified by means of a cubic RBF response surface approach. Findings The separation was significantly reduced, modifying the local geometry of fuselage and fairing and maintaining the wing aerofoil unchanged. A relevant aerodynamic efficiency improvement was finally gained. Practical implications The developed procedure proved to be a very powerful and efficient tool in facing aerodynamic design problems. However, it might be computationally very expensive if a large number of design variables are adopted and, in those cases, the method can be suitably used only within the HPC environment. Originality/value Such an optimization study is part of an explorative set of analyses that focused on better addressing the numerical strategies to be used in the development of the EU FP7 Project RBF4AERO.

Polarized perceptions, polarized preferences? Understanding the relationship between inequality and preferences for redistribution

2019 ◽  
Vol 30 (2) ◽  
pp. 206-224
Author(s):  
Licia Bobzien
Keyword(s):  
Regression Analysis ◽  
Control Variables ◽  
Preferences For Redistribution ◽  
Common Control ◽  
Simple Regression Analysis ◽  
The Common ◽  
Unexplained Variance ◽  
Socio Economic Variables ◽  
The Relationship ◽  
Simple Regression

When studying the relationship between inequality and preferences for redistribution, it is often assumed – either implicitly or explicitly – that individuals are informed about actual levels of inequality. Newer research, however, challenges this assumption and shows that perceived inequality differs from actual inequality. Empirically, these inequality perceptions are rather good predictors for preferences for redistribution. This article argues that individuals answer the standard question for measuring preferences for redistribution based on their inequality perceptions. I conduct a simple regression analysis based on two waves of the ISSP (1999 and 2009) and show that (1) inequality perceptions are systematically linked to socio-economic variables as well as to ideological beliefs rather than to actual inequality. Then, I disaggregate the variance in inequality perceptions to a part which is explainable by socio-economic and ideological determinants (the common control variables for explaining preferences for redistribution) and an unexplained part. I show that (2) the explained as well as the unexplained variance part is associated with preferences for redistribution. I argue that this finding makes considering inequality perceptions practically relevant since standard control variables do not fully account for variation in perceived inequality.

scholarly journals Chlamydial contribution to anaerobic metabolism during eukaryotic evolution

2020 ◽  
Vol 6 (35) ◽  
pp. eabb7258 ◽  
Author(s):  
Courtney W. Stairs ◽  
Jennah E. Sharamshi ◽  
Daniel Tamarit ◽  
Laura Eme ◽  
Steffen L. Jørgensen ◽  
...  
Keyword(s):  
Marine Sediments ◽  
Evolutionary Biology ◽  
Anaerobic Metabolism ◽  
Phylogenetic Analyses ◽  
Eukaryotic Evolution ◽  
Present Evidence ◽  
Multiple Hypotheses ◽  
Key Genes ◽  
Open Question ◽  
Origin Of Eukaryotes

The origin of eukaryotes is a major open question in evolutionary biology. Multiple hypotheses posit that eukaryotes likely evolved from a syntrophic relationship between an archaeon and an alphaproteobacterium based on H2 exchange. However, there are no strong indications that modern eukaryotic H2 metabolism originated from archaea or alphaproteobacteria. Here, we present evidence for the origin of H2 metabolism genes in eukaryotes from an ancestor of the Anoxychlamydiales—a group of anaerobic chlamydiae, newly described here, from marine sediments. Among Chlamydiae, these bacteria uniquely encode genes for H2 metabolism and other anaerobiosis-associated pathways. Phylogenetic analyses of several components of H2 metabolism reveal that Anoxychlamydiales homologs are the closest relatives to eukaryotic sequences. We propose that an ancestor of the Anoxychlamydiales contributed these key genes during the evolution of eukaryotes, supporting a mosaic evolutionary origin of eukaryotic metabolism.

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