scholarly journals JuliaFEM - open source solver for both industrial and academia usage

2017 ◽  
Vol 50 (3) ◽  
pp. 229-233 ◽  
Author(s):  
Tero Frondelius ◽  
Jukka Aho
Keyword(s):  
Design Principle ◽  
Distributed Processing ◽  
Scale Up ◽  
Programming Models ◽  
Finite Element Models ◽  
Software Library ◽  
Local Computation ◽  
Special Cases ◽  
Non Linear ◽  
And Storage

The JuliaFEM software library is a framework that allows for the distributed processing of large Finite Element Models across clusters of computers using simple programming models. It is designed to scale up from single servers to thousands of machines, each offering local computation and storage. The basic design principle is: Everything is non-linear. All physics models are non-linear from which the linearizations are made as special cases. This is work in progress. Thus, if you share the vision, contribute and join the community. 

scholarly journals A New Approach to Compensator Design Based on Multi-Loop Technique and Scalable Forward Model Complexity

Electronics ◽  
2021 ◽  
Vol 10 (24) ◽  
pp. 3049
Author(s):  
Rafał Osypiuk
Keyword(s):  
Process Model ◽  
Position Control ◽  
Control Method ◽  
Scale Up ◽  
Model Complexity ◽  
Linear Processes ◽  
New Approach ◽  
Special Cases ◽  
Non Linear ◽  
Forward Process

Using a compensator in the structure is one of the simplest ways to achieve efficient control of a non-linear process. Unfortunately, accessing the inverse process model is not a trivial issue. Except for some special cases, it is much easier to determine the forward process model than the inverse one. For this reason, it would be interesting to propose an alternative solution to the well-known feedforward control method. In this paper, a simple multi-loop concept will be introduced. The main idea is based on the natural (but limited) robustness offered by a single PID loop and the ability to scale up the complexity of the forward process model. The proposed structure multiplies a single PID loop including forward models with increasing complexity to calculate the resultant non-linear control value. This new approach produces a comparable performance to the feedforward method but does not require access to the inverse properties of the process. The idea was evaluated in terms of stability and robustness to parameter changes. In addition, a simulation study was carried out using two coupled non-linear processes, i.e., the position control of a robot manipulator with force interaction. The selection of this process was no casual choice. On the one hand, it is extremely complex; however, on the other hand, it provides the possibility to determine both the inverse and the forward dynamic model. This capability was helpful to perform an effective comparison of the proposed solution with the known feedforward structure.

Control of arrivals to a stochastic input–output system

1980 ◽  
Vol 12 (4) ◽  
pp. 972-999 ◽  
Author(s):  
Søren Glud Johansen ◽  
Shaler Stidham
Keyword(s):  
Markov Decision Process ◽  
Decision Process ◽  
Input Output ◽  
Distinctive Features ◽  
Control Models ◽  
Special Cases ◽  
Non Linear ◽  
Markov Decision ◽  
Output System ◽  
Stochastic Input

The problem of controlling input to a stochastic input-output system by accepting or rejecting arriving customers is analyzed as a semi-Markov decision process. Included as special cases are a GI/G/1 model and models with compound input and/or output processes, as well as several previously studied queueing-control models. We establish monotonicity of socially and individually optimal acceptance policies and the more restrictive nature of the former, with random rewards for acceptance and both customer-oriented and system-oriented non-linear waiting costs. Distinctive features of our analysis are (i) that it allows dependent interarrival times and (ii) that the monotonicity proofs do not rely on the standard concavity-preservation arguments.

AN ADVANCED ADAPTIVE FINITE ELEMENT CODE APPLIED FOR COATING-SUBSTRATE SIMULATION

2011 ◽  
Vol 03 (01n02) ◽  
pp. 91-107 ◽  
Author(s):  
JÜRGEN LEOPOLD ◽  
KATRIN HELLER ◽  
ARNDT MEYER ◽  
REINER WOHLGEMUTH
Keyword(s):  
Finite Element ◽  
Fe Simulation ◽  
Scale Up ◽  
Computational Time ◽  
Adaptive Finite Element ◽  
Workpiece Surface ◽  
Coated Tools ◽  
Geometrical Simulation ◽  
The Stability ◽  
And Storage

The stability of coating-substrate systems influences the chip formation and the surface integrity of the new generated workpiece surface, too. Using finite element (FE) simulation, deformations, strains and stresses in coated tools, caused by external and internal loads, can be computed on a microscopic scale. Since both, the whole macroscopic tool (in mm-scale) and the microscopic coating layers (in μm-scale up to nm-scale) must be included in the same geometrical simulation model, graded high-resolution FE meshes must be used. Nevertheless, the number of nodes in the 3D computational FE grid reaches some millions, leading to large computational time and storage requirements. For this reason, an advanced adaptive finite element (AAFEM) software has been developed and used for the simulation.

Keysystems in large systems implementing distributed data processing and storage technologies

2021 ◽  
Author(s):  
V.G. Belenkov ◽  
V.I. Korolev ◽  
V.I. Budzko ◽  
D.A. Melnikov
Keyword(s):  
Data Processing ◽  
Distributed Processing ◽  
Specific Work ◽  
Distributed Data ◽  
Distributed Data Processing ◽  
Technical Specifications ◽  
The Creation ◽  
Processing And Storage ◽  
Storage Technologies ◽  
And Storage

The article discusses the features of the use of the cryptographic information protection means (CIPM)in the environment of distributed processing and storage of data of large information and telecommunication systems (LITS).A brief characteristic is given of the properties of the cryptographic protection control subsystem - the key system (CS). A description is given of symmetric and asymmetric cryptographic systems, required to describe the problem of using KS in LITS.Functional and structural models of the use of KS and CIPM in LITS, are described. Generalized information about the features of using KS in LITS is given. The obtained results form the basis for further work on the development of the architecture and principles of KS construction in LITS that implement distributed data processing and storage technologies. They can be used both as a methodological guide, and when carrying out specific work on the creation and development of systems that implement these technologies, as well as when forming technical specifications for the implementation of work on the creation of such systems.

scholarly journals Non-linear integral equations for Heun functions

1969 ◽  
Vol 16 (4) ◽  
pp. 281-289 ◽  
Author(s):  
B. D. Sleeman
Keyword(s):  
Integral Equations ◽  
Heun Equation ◽  
Mathieu Functions ◽  
Special Cases ◽  
Mathieu’S Equation ◽  
Heun Functions ◽  
Non Linear ◽  
Linear Integral ◽  
Image Position ◽  
Linear Integral Equations

Some years ago Lambe and Ward (1) and Erdélyi (2) obtained integral equations for Heun polynomials and Heun functions. The integral equations discussed by these authors were of the formFurther, as is well known, the Heun equation includes, among its special cases, Lamé's equation and Mathieu's equation and so (1.1) may be considered a generalisation of the integral equations satisfied by Lamé polynomials and Mathieu functions. However, integral equations of the type (1.1) are not the only ones satisfied by Lamé polynomials; Arscott (3) discussed a class of non- linear integral equations associated with these functions. This paper then is concerned with discussing the existence of non-linear integral equations satisfied by solutions of Heun's equation.

scholarly journals A Pattern-Based Method for Re-Engineering Non-Ontological Resources into Ontologies

2010 ◽  
Vol 6 (4) ◽  
pp. 27-63 ◽  
Author(s):  
Boris Carmen Villazón-Terrazas ◽  
Mari Suárez-Figueroa ◽  
Asunción Gómez-Pérez
Keyword(s):  
Data Model ◽  
Development Process ◽  
Storage System ◽  
Ontology Development ◽  
Software Library ◽  
Process Ontology ◽  
Classification Schemes ◽  
Speed Up ◽  
And Storage

To speed up the ontology development process, ontology developers are reusing all available ontological and non-ontological resources, such as classification schemes, thesauri, lexicons, and so forth, that have already reached some consensus. Non-ontological resources are highly heterogeneous in their data model and storage system (or implementation). The reuse of these non-ontological resources involves their re-engineering into ontologies. This paper presents a method for re-engineering non-ontological resources into ontologies. The method is based on so-called re-engineering patterns, which define a procedure that transforms the non-ontological resource components into ontology representational primitives using WordNet for making explicit the relations among the non-ontological resource terms. The paper also provides the description of NOR2O, a software library that implements the transformations suggested by the patterns. Finally, it depicts an evaluation of the method, patterns, and software library proposed.

Non-linear wave-number interaction in near-critical two-dimensional flows

1971 ◽  
Vol 49 (4) ◽  
pp. 705-744 ◽  
Author(s):  
R. C. Diprima ◽  
W. Eckhaus ◽  
L. A. Segel
Keyword(s):  
Travelling Waves ◽  
Fundamental Equation ◽  
Linear Partial Differential Equation ◽  
Original System ◽  
Basic Flow ◽  
Linear Stability Theory ◽  
Wave Number ◽  
Linear Wave ◽  
Special Cases ◽  
Non Linear

This paper deals with a system of equations which includes as special cases the equations governing such hydrodynamic stability problems as the Taylor problem, the Bénard problem, and the stability of plane parallel flow. A non-linear analysis is made of disturbances to a basic flow. The basic flow depends on a single co-ordinate η. The disturbances that are considered are represented as a superposition of many functions each of which is periodic in a co-ordinate ξ normal to η and is independent of the third co-ordinate direction. The paper considers problems in which the disturbance energy is initially concentrated in a denumerable set of ‘most dangerous’ modes whose wave-numbers are close to the critical wave-number selected by linear stability theory. It is a major result of the analysis that this concentration persists as time passes. Because of this the problem can be reduced to the study of a single non-linear partial differential equation for a special Fourier transform of the modal amplitudes. It is a striking feature of the present work that the study of a wide class of problems reduces to the study of this single fundamental equation which does not essentially depend on the specific forms ofthe operators in the original system of governing equations. Certain general conclusions are drawn from this equation, for example for some problems there exist multi-modal steady solutions which are a combination of a number of modes with different spatial periods. (Whether any such solutions are stable remains an open question.) It is also shown in other circumstances that there are solutions (at least for some interval of time) which are non-linear travelling waves whose kinematic behaviour can be clarified by the concept of group speed.

Mixed Integer Non-Linear Programming models for Green Network Design

2013 ◽  
Vol 40 (1) ◽  
pp. 273-281 ◽  
Author(s):  
Rosario G. Garroppo ◽  
Stefano Giordano ◽  
Gianfranco Nencioni ◽  
Maria Grazia Scutellà
Keyword(s):  
Linear Programming ◽  
Network Design ◽  
Programming Models ◽  
Mixed Integer ◽  
Non Linear Programming ◽  
Non Linear
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