scholarly journals Evaluations of An Algorithm for Large Multivariate Optimization

2021 ◽  
Vol 2068 (1) ◽  
pp. 012026
Author(s):  
Yoel Tenne
Keyword(s):  
Numerical Experiments ◽  
Search Space ◽  
Multivariate Optimization ◽  
Simplified Approach ◽  
Size Dimension ◽  
Lower Size

Abstract Many simulation-driven engineering and scientific problems require finding an optimum of a function with many variables. Such settings pose a challenge for standard algorithms due to the large search space which in turn can lead to poor final results. Therefore this paper proposes a new simplified approach in which the dimension of the problem is dynamically reduced during the search to formulate a problem of lower size (dimension) which is easier to solve. A main novelty of the algorithm is its simplicity. Numerical experiments show the potential of this approach.

Mixed Lubrication Analyses by a Macro-Micro Approach and a Full-Scale Mixed EHL Model

2004 ◽  
Vol 126 (1) ◽  
pp. 81-91 ◽  
Author(s):  
Q. Jane Wang ◽  
Dong Zhu ◽  
Herbert S. Cheng ◽  
Tonghui Yu ◽  
Xiaofei Jiang ◽  
...  
Keyword(s):  
Pressure Distribution ◽  
Numerical Experiments ◽  
Flow Model ◽  
Elastohydrodynamic Lubrication ◽  
Full Scale ◽  
Asperity Contact ◽  
Average Pressure ◽  
Average Flow ◽  
Simplified Approach ◽  
Average Flow Model

This paper presents an improvement of a simplified approach, namely, the macro-micro approach, used to model the mixed elastohydrodynamic lubrication problems in counterformal contacts, and its comparison with Zhu and Hu’s full-scale mixed-EHL model. In this approach, Patir and Cheng’s average flow model is employed to obtain the distribution of piecewise average pressure. A contact-embedment method that incorporates the detail of asperity contact pressure into the overall pressure distribution is utilized to reveal the severity of surface interaction. Numerical experiments are conducted, and the results are compared with those obtained by means of the full-scale mixed-EHL. The regime of the application of this macro-micro approach is explored.

Fiscal rules: Excessive limitation or indispensable instrument of fiscal sustainability?

2016 ◽  
pp. 5-29 ◽  
Author(s):  
E. Gurvich ◽  
I. Sokolov
Keyword(s):  
Historical Data ◽  
Federal Budget ◽  
Fiscal Sustainability ◽  
Fiscal Rules ◽  
External Shocks ◽  
Base Price ◽  
Depth Analysis ◽  
Fiscal Balance ◽  
Lower Size ◽  
Budget Expenditure

In-depth analysis of international and Russia’s experiences with implementing fiscal rules is presented. Theoretical and empirical evidences are suggested in favor of retaining the present fiscal rules with some modifications aimed at ensuring: a) a relatively stable level of federal budget expenditure with guaranteed full execution of all commitments; b) countercyclical fiscal policy, based on flexibleand proper reaction to revenue changes; and c) robustness of fiscal rules to internal and external shocks. The main new features suggested include modified calculation of the oil base price, different measurement of cyclical fiscal revenues, lower size of structural fiscal balance, and thorough specification of sources for each item of the balance. The modified rules envisage increased flexibility by relaxing to a pre-set extent and for a pre-set time spending limits in response to extreme shocks. The suggested version of fiscal rules has been tested by application to historical data for 2005-2015, and macro projections for 2015-2025.

Simplified Approach to Calculating Geometric Stiffness Properties of Tread Pattern Elements

2003 ◽  
Vol 31 (3) ◽  
pp. 132-158 ◽  
Author(s):  
R. E. Okonieski ◽  
D. J. Moseley ◽  
K. Y. Cai
Keyword(s):  
Development Process ◽  
Functional Design ◽  
Simplified Approach ◽  
Tire Industry ◽  
Geometric Stiffness ◽  
Stiffness Properties ◽  
Engineering Parameters ◽  
Net To Gross ◽  
Significant Effort

Abstract The influence of tread designs on tire performance is well known. The tire industry spends significant effort in the development process to create and refine tread patterns. Creating an aesthetic yet functional design requires characterization of the tread design using many engineering parameters such as stiffness, moments of inertia, principal angles, etc. The tread element stiffness is of particular interest because of its use to objectively determine differences between tread patterns as the designer refines the design to provide optimum levels of performance. The tread designer monitors the change in stiffness as the design evolves. Changes to the geometry involve many attributes including the number of sipes, sipe depth, sipe location, block element edge taper, nonskid depth, area net-to-gross, and so forth. In this paper, two different formulations for calculating tread element or block stiffness are reviewed and are compared to finite element results in a few cases. A few simple examples are shown demonstrating the basic functionality that is possible with a numerical method.

Controllable Compliance Joint For Human Oriented Robots

2013 ◽  
Vol 43 (1) ◽  
pp. 47-60
Author(s):  
Mihail Tsveov ◽  
Dimitar Chakarov
Keyword(s):  
Numerical Experiments ◽  
Position Control ◽  
Joint Stiffness ◽  
Joint Motion ◽  
Compliance Control ◽  
Leaf Springs ◽  
Antagonistic Actuation

Abstract In the paper, different approaches for compliance control for human oriented robots are revealed. The approaches based on the non- antagonistic and antagonistic actuation are compared. In addition, an approach is investigated in this work for the compliance and the position control in the joint by means of antagonistic actuation. It is based on the capability of the joint with torsion leaf springs to adjust its stiffness. Models of joint stiffness are presented in this paper with antagonistic and non-antagonistic influence of the spring forces on the joint motion. The stiffness and the position control possibilities are investigated and the opportunity for their decoupling as well. Some results of numerical experiments are presented in the paper too.

A Simplified Protocol for the ortho-Deuteration of Acidic Aromatic Compounds in D2O

2019 ◽  
Author(s):  
Alyssa Garreau ◽  
Hanyang Zhou ◽  
Michael Young
Keyword(s):  
Carboxylic Acid ◽  
Aromatic Compounds ◽  
Large Scale ◽  
Simplified Approach ◽  
Directing Group ◽  
Large Scale Synthesis

<div>Methods to catalytically introduce deuterium in synthetically useful yields ortho to a carboxylic acid directing group on arenes typically requires D2 or CD3CO2D, which makes using these approaches cost prohibitive for large scale synthesis (equipment and reagent costs respectively). Herein we present a simplified approach using catalytic RhIII and D2O as deuterium source, and show its application to H/D exchange on various acidic substrates.</div>

Sign in / Sign up

Export Citation Format

Share Document