Combined Analysis and Optimization of Extended Heat Transfer Surfaces

1985 ◽  
Vol 107 (3) ◽  
pp. 527-532 ◽  
Author(s):  
A. N. Hrymak ◽  
G. J. McRae ◽  
A. W. Westerberg
Keyword(s):  
Optimization Problem ◽  
Radiative Heat ◽  
Inequality Constraints ◽  
Finite Element Approximation ◽  
Problem Formulation ◽  
Element Approximation ◽  
Problem Solution ◽  
Radiative Heat Loss ◽  
Equality And Inequality Constraints ◽  
Grid Points

This study presents an efficient numerical method to discover the optimal shape for a fin subject to both convective and radiative heat loss. Problem formulation is a finite element approximation to the conduction equation embedded within and solved simultaneously with the shape optimization problem. The approach handles arbitrary equality and inequality constraints. Grid points move to conform to the fin shape during the problem solution, reducing the number of elements required in the solution.

Inverse Kinematics of Redundant Manipulators Formulated as Quadratic Programming Optimization Problem Solved Using Recurrent Neural Networks: A Review

Robotica ◽  
2019 ◽  
Vol 38 (8) ◽  
pp. 1495-1512
Author(s):  
Ahmed A. Hassan ◽  
Mohamed El-Habrouk ◽  
Samir Deghedie
Keyword(s):  
Neural Networks ◽  
Quadratic Programming ◽  
Recurrent Neural Networks ◽  
Inverse Kinematics ◽  
Optimization Problem ◽  
Problem Formulation ◽  
Joint Space ◽  
Problem Solution ◽  
Redundant Manipulators ◽  
Joint Angles

SUMMARYThe Inverse Kinematics (IK) problem of manipulators can be divided into two distinct steps: (1) Problem formulation, where the problem is developed into a form which can then be solved using various methods. (2) Problem solution, where the IK problem is actually solved by producing the values of different joint space variables (joint angles, joint velocities or joint accelerations). The main focus of this paper is concentrated on the discussion of the IK problem of redundant manipulators, formulated as a quadratic programming optimization problem solved by different kinds of recurrent neural networks.

FINITE ELEMENT APPROXIMATION OF NONLOCAL HEAT RADIATION PROBLEMS

1998 ◽  
Vol 08 (06) ◽  
pp. 1071-1089 ◽  
Author(s):  
T. TIIHONEN
Keyword(s):  
Finite Element ◽  
Error Analysis ◽  
Radiative Heat ◽  
Finite Element Approximation ◽  
Heat Radiation ◽  
Nonlocal Term ◽  
Radiative Heat Exchange ◽  
Element Approximation ◽  
Heat Transfers ◽  
Continuous Problem

This paper focuses on finite element error analysis for problems involving both conductive and radiative heat transfers. The radiative heat exchange is modeled with a nonlinear and nonlocal term that also makes the problem non-monotone. The continuous problem has a maximum principle which suggests the use of inverse monotone discretizations. We also estimate the error due to the approximation of the boundary by showing continuous dependence on the geometric data for the continuous problem. The final result of this paper is a rigorous justification and error analysis for methods that use the so-called view factors for numerical modeling of the heat radiation.

scholarly journals An MPC Approach for Grid-Forming Inverters: Theory and Experiment

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2270 ◽  
Author(s):  
Alessandro Labella ◽  
Filip Filipovic ◽  
Milutin Petronijevic ◽  
Andrea Bonfiglio ◽  
Renato Procopio
Keyword(s):  
Operation Mode ◽  
Inequality Constraints ◽  
Problem Formulation ◽  
Management Control ◽  
Power Electronic ◽  
Power Electronic Converters ◽  
Correct Operation ◽  
Equality And Inequality Constraints ◽  
Local Measurements ◽  
Set Up

Microgrids (MGs) interest is growing very fast due to the environment urgency and their capability to integrate renewable energy in a flexible way. In particular, islanded MGs in which distributed energy resources (DERs) are connected to the infrastructure with power electronic converters have attracted the interest of many researchers of both academia and industry because management, control and protection of such systems is quite different from the case of traditional networks. According to their operation mode, MGs that power electronic converters can be divided into grid-forming, grid-feeding and grid-supporting inverters. In particular, grid forming inverters are asked to impose voltage and frequency in the MG. This paper aims to propose a model predictive control (MPC) based approach for grid-forming inverters in an islanded MG. The MPC strategy is implemented because of its capability to define the optimal control actions that contemporarily track the desired reference signals and accounts for equality and inequality constraints. The overall problem formulation (objective function and relevant constraints) is described step by step and considers the specificity of the considered DC source. The proposed approach allows for the obtaining of very good results in terms of readiness against disturbances, even if it requires being fed only by local measurements. In order to validate the developed method, this paper proposes an experimental validation of the designed MPC controller in order to show its correct operation on a real system in a power hardware in the loop set-up using a rapid control prototyping approach.

scholarly journals Hypervolume scalarization for shape optimization to improve reliability and cost of ceramic components

2021 ◽  
Author(s):  
Johanna Schultes ◽  
Michael Stiglmayr ◽  
Kathrin Klamroth ◽  
Camilla Hahn
Keyword(s):  
Shape Optimization ◽  
Optimization Problem ◽  
Mechanical Stability ◽  
Adjoint Equation ◽  
Tensile Load ◽  
Problem Formulation ◽  
State Equation ◽  
Efficient Solutions ◽  
Volume Stability ◽  
Shape Optimization Problem

AbstractIn engineering applications one often has to trade-off among several objectives as, for example, the mechanical stability of a component, its efficiency, its weight and its cost. We consider a biobjective shape optimization problem maximizing the mechanical stability of a ceramic component under tensile load while minimizing its volume. Stability is thereby modeled using a Weibull-type formulation of the probability of failure under external loads. The PDE formulation of the mechanical state equation is discretized by a finite element method on a regular grid. To solve the discretized biobjective shape optimization problem we suggest a hypervolume scalarization, with which also unsupported efficient solutions can be determined without adding constraints to the problem formulation. FurthIn this section, general properties of the hypervolumeermore, maximizing the dominated hypervolume supports the decision maker in identifying compromise solutions. We investigate the relation of the hypervolume scalarization to the weighted sum scalarization and to direct multiobjective descent methods. Since gradient information can be efficiently obtained by solving the adjoint equation, the scalarized problem can be solved by a gradient ascent algorithm. We evaluate our approach on a 2 D test case representing a straight joint under tensile load.

scholarly journals Optimization-Based Formulations for Short-Circuit Studies with Inverter-Interfaced Generation in PowerModelsProtection.jl

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2160
Author(s):  
Arthur K. Barnes ◽  
Jose E. Tabarez ◽  
Adam Mate ◽  
Russell W. Bent
Keyword(s):  
Optimization Problem ◽  
Short Circuit ◽  
Problem Formulation ◽  
Power Delivery ◽  
Fault Current ◽  
Protective Device ◽  
Protective Relaying ◽  
Overcurrent Protection ◽  
Short Circuits ◽  
Optimization Problem Formulation

Protecting inverter-interfaced microgrids is challenging as conventional time-overcurrent protection becomes unusable due to the lack of fault current. There is a great need for novel protective relaying methods that enable the application of protection coordination on microgrids, thereby allowing for microgrids with larger areas and numbers of loads while not compromising reliable power delivery. Tools for modeling and analyzing such microgrids under fault conditions are necessary in order to help design such protective relaying and operate microgrids in a configuration that can be protected, though there is currently a lack of tools applicable to inverter-interfaced microgrids. This paper introduces the concept of applying an optimization problem formulation to the topic of inverter-interfaced microgrid fault modeling, and discusses how it can be employed both for simulating short-circuits and as a set of constraints for optimal microgrid operation to ensure protective device coordination.

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