Quantitative Szegő Minimum Problem for Some non-Szegő Measures

2021 ◽  
pp. 123-127
Author(s):  
Anna Kononova
Keyword(s):  
Minimum Problem

scholarly journals Optimal control in liver kinetics

1986 ◽  
Vol 27 (3) ◽  
pp. 361-369 ◽  
Author(s):  
A. M. Fink
Keyword(s):  
Optimal Control ◽  
Minimization Problem ◽  
Enzymatic Reaction ◽  
The Body ◽  
Minimum Problem ◽  
Density Functions ◽  
Intermediate Form

AbstractWe solve a minimization problem in liver kinetics posed by Bass, et al., in this journal, (1984), pages 538–562. The problem is to choose the density functions for the location of two enzymes, in order to minimize the concentration of an intermediate form of a substance at the outlet of the liver. This form may be toxic to the rest of the body, but the second enzyme renders it harmless. It seems natural that the second enzyme should be downstream from the first. However, we can show that the minimum problem is sometimes solved by an overlap of the supports of the two density functions. Even more surprising is that, for certain forms of the kinetic functions and high levels of transformation of the first enzymatic reaction, some of the first enzyme should be located downstream from all the second enzyme. This suggests that the first reaction should be relatively slow.

scholarly journals Fuzzy Formation Control and Collision Avoidance for Multiagent Systems

2013 ◽  
Vol 2013 ◽  
pp. 1-18 ◽  
Author(s):  
Yeong-Hwa Chang ◽  
Chun-Lin Chen ◽  
Wei-Shou Chan ◽  
Hung-Wei Lin ◽  
Chia-Wen Chang
Keyword(s):  
Collision Avoidance ◽  
Multiagent Systems ◽  
Formation Control ◽  
Descent Method ◽  
Minimum Problem ◽  
Gradient Descent Method ◽  
Consensus Formation ◽  
Distributed Information ◽  
Graph Theoretic ◽  
Learning Rules

This paper aims to investigate the formation control of leader-follower multiagent systems, where the problem of collision avoidance is considered. Based on the graph-theoretic concepts and locally distributed information, a neural fuzzy formation controller is designed with the capability of online learning. The learning rules of controller parameters can be derived from the gradient descent method. To avoid collisions between neighboring agents, a fuzzy separation controller is proposed such that the local minimum problem can be solved. In order to highlight the advantages of this fuzzy logic based collision-free formation control, both of the static and dynamic leaders are discussed for performance comparisons. Simulation results indicate that the proposed fuzzy formation and separation control can provide better formation responses compared to conventional consensus formation and potential-based collision-avoidance algorithms.

Existence theorem for a minimum problem with free discontinuity set

1989 ◽  
Vol 108 (4) ◽  
pp. 195-218 ◽  
Author(s):  
E. De Giorgi ◽  
M. Carriero ◽  
A. Leaci
Keyword(s):  
Existence Theorem ◽  
Minimum Problem

A Robust Method with High Time Resolution for Estimating the Cortico-Thalamo-Cortical Loop Strength and the Delay when Using a Scalp Electroencephalography Applied to the Wake-Sleep Transition

2018 ◽  
Vol 57 (03) ◽  
pp. 122-128 ◽  
Author(s):  
Akifumi Kishi ◽  
Fumiharu Togo ◽  
Toru Nakamura ◽  
Yoshiharu Yamamoto ◽  
Ikuhiro Yamaguchi
Keyword(s):  
Transfer Function ◽  
Time Resolution ◽  
Physiological Model ◽  
High Time ◽  
Ar Model ◽  
Minimum Problem ◽  
High Time Resolution ◽  
Robust Method ◽  
Loop Delay ◽  
Sleep Transition

Summary Objectives: This study aimed to describe a robust method with high time resolution for estimating the cortico-thalamo-cortical (CTC) loop strength and the delay when using a scalp electroencephalography (EEG) and to illustrate its applicability for analyzing the wake-sleep transition. Methods: The basic framework for the proposed method is the parallel use of a physiological model and a parametric phenomenological model: a neural field theory (NFT) of the corticothalamic system and an autoregressive (AR) model. The AR model is a “stochastic” model that shortens the time taken to extract spectral features and is also a “linear” model that is free from the local-minimum problem. From the relationship between the transfer function of the AR model and the transfer function of the NFT in the low frequency limit, we successfully derived a direct expression of CTC loop strength and the loop delay using AR coefficients. Results: Using this method to analyze sleep-EEG data, we were able to clearly track the wake-to-sleep transition, as the estimated CTC loop strength (c 2) decreased to almost zero. We also found that the c 2-distribution during nocturnal sleep is clearly bimodal in nature, which can be well approximated by the superposition of two Gaussian distributions that correspond to sleep and wake states, respectively. The estimated loop delay distributed ∼0.08 s, which agrees well with the previously reported value estimated by other methods, confirming the validity of our method. Conclusions: A robust method with high time resolution was developed for estimating the cortico-thalamo-cortical loop strength and the delay when using a scalp electroencephalography. This method can contribute not only to detecting the wake-sleep transition, but also to further understanding of the transition, where the cortico-thalamo-cortical loop is thought to play an important role.

scholarly journals Modified Elman Neural-PID Controller Design for DC-DC Buck Converter System Based on Dolphin Echolocation Optimization

2018 ◽  
Vol 14 (3) ◽  
pp. 129-140
Author(s):  
Khulood E. Dagher
Keyword(s):  
Pid Controller ◽  
Controller Design ◽  
Load Resistance ◽  
Buck Converter ◽  
Minimum Problem ◽  
Portable Devices ◽  
Elman Neural Network ◽  
Pid Controller Design ◽  
On Line ◽  
Local Minimum Problem

This paper describes a new proposed structure of the Proportional Integral Derivative (PID) controller based on modified Elman neural network for the DC-DC buck converter system which is used in battery operation of the portable devices. The Dolphin Echolocation Optimization (DEO) algorithm is considered as a perfect on-line tuning technique therefore, it was used for tuning and obtaining the parameters of the modified Elman neural-PID controller to avoid the local minimum problem during learning the proposed controller. Simulation results show that the best weight parameters of the proposed controller, which are taken from the DEO, lead to find the best action and unsaturated state that will stabilize the Buck converter system performance and achieve the desired output. In addition, there is a minimization for the tracking voltage error to zero value of the Buck converter output, especially when changing a load resistance by 10%.

Optimal Trajectories and the Accessory Minimum Problem

1965 ◽  
Vol 16 (3) ◽  
pp. 205-220 ◽  
Author(s):  
D. J. Bell
Keyword(s):  
Necessary Conditions ◽  
Sounding Rocket ◽  
Necessary Condition ◽  
Minimum Problem ◽  
Multiplier Rule ◽  
Variation Of A Function ◽  
Accessory Minimum Problem ◽  
The First Variation ◽  
The Second Variation

SummaryThe necessary conditions of Clebsch and Weierstrass and of the multiplier rule in the calculus of variations, which arise from the study of the first variation of a function, are summarised. A further necessary condition associated with the second variation is stated. The latter condition is applied to two problems: (i) the determination of the thrust-time programme which maximises the altitude of a sounding rocket, (ii) the determination of the thrust direction programme for a rocket with a known propellant expenditure programme which yields a maximum range. In both problems it is found that the additional necessary condition is satisfied.

Sign in / Sign up

Export Citation Format

Share Document