Optimizing Locator Position to Maximize Robustness in Critical Product Dimensions

2009 ◽  
Author(s):  
Johan Lo¨o¨f ◽  
Lars Lindkvist ◽  
Rikard So¨derberg
Keyword(s):  
Optimization Problem ◽  
Heuristic Approach ◽  
Critical Dimensions ◽  
Early Design ◽  
Geometrical Variation ◽  
Production Problems ◽  
The Way

The way parts are located in relation to each other or in fixtures is critical for how geometrical variation will propagate and cause variation in critical product dimensions. Therefore, more emphasis should be put on this activity in early design phases in order to avoid assembly and production problems later on. In earlier literature, locator positions have been defined using optimization to reach a robust locating scheme. This implies that the total robustness of a part is optimized by placing the locators in an optimal way. Sometimes there are areas on parts that are more sensitive to variation than others. Therefore, this paper suggests an approach for optimizing the positions of locators in a locating scheme to maximize robustness in defined critical dimensions. A formulation of an optimization problem is presented, and an algorithm solving this in a heuristic approach is developed. Finally, this algorithm is applied on an industrial example.

Optimal Subassembly Partitioning of Space Frame Structures for In-Process Dimensional Adjustability and Stiffness

2005 ◽  
Vol 128 (3) ◽  
pp. 527-535 ◽  
Author(s):  
Naesung Lyu ◽  
Byungwoo Lee ◽  
Kazuhiro Saitou
Keyword(s):  
Cross Sections ◽  
Optimization Problem ◽  
Vehicle Body ◽  
Structural Stiffness ◽  
Unified Framework ◽  
Space Frame ◽  
Critical Dimensions ◽  
Optimization Routine ◽  
The Given

A method for optimally synthesizing multicomponent structural assemblies of an aluminum space frame (ASF) vehicle body is presented, which simultaneously considers structural stiffness, manufacturing and assembly costs and dimensional integrity under a unified framework based on joint libraries. The optimization problem is posed as a simultaneous determination of the location and feasible types of joints in a structure selected from the predefined joint libraries, combined with the size optimization for the cross sections of the joined structural frames. The structural stiffness is evaluated by finite element analyses of a beam-spring model modeling the joints and joined frames. Manufacturing and assembly costs are estimated based on the geometries of the components and joints. Dissimilar to the enumerative approach in our previous work, dimensional integrity of a candidate assembly is evaluated as the adjustability of the given critical dimensions, using an internal optimization routine that finds the optimal subassembly partitioning of an assembly for in-process adjustability. The optimization problem is solved by a multiobjective genetic algorithm. An example on an ASF of the midsize passenger vehicle is presented, where the representative designs in the Pareto set are examined with respect to the three design objectives.

Decomposition-Based Assembly Synthesis for Structural Stiffness and Dimensional Integrity

2004 ◽  
Author(s):  
Naesung Lyu ◽  
Byungwoo Lee ◽  
Kazuhiro Saitou
Keyword(s):  
Cross Sections ◽  
Optimization Problem ◽  
Vehicle Body ◽  
Structural Stiffness ◽  
Passenger Vehicle ◽  
Unified Framework ◽  
Critical Dimensions ◽  
Multi Objective Genetic Algorithm ◽  
The Given

A method for optimally synthesizing multi-component structural assemblies of an aluminum space frame (ASF) vehicle body is presented, which simultaneously considers structural stiffness, manufacturing and assembly cost and dimensional integrity under a unified framework based on joint libraries. The optimization problem is posed as a simultaneous determination of the location and feasible types of joints in a structure selected from the predefined joint libraries, combined with the size optimization for the cross sections of the joined structural frames. The structural stiffness is evaluated by finite element analyses of a beam-spring model modeling the joints and joined frames. Manufacturing and assembly costs are estimated based on the geometries of the components and joints. Dimensional integrity is evaluated as the adjustability of the assembly for the given critical dimensions. The optimization problem is solved by a multi-objective genetic algorithm. An example on an ASF of the mid-size passenger vehicle is presented, where the representative designs in the Pareto set are examined with respect to the three design objectives.

scholarly journals A heuristic approach to the hyperparameters in training spiking neural networks using spike-timing-dependent plasticity

2021 ◽  
Author(s):  
Dawid Połap ◽  
Marcin Woźniak ◽  
Waldemar Hołubowski ◽  
Robertas Damaševičius
Keyword(s):  
Neural Networks ◽  
Optimization Problem ◽  
Heuristic Algorithms ◽  
Search Algorithm ◽  
Cuckoo Search ◽  
Spike Timing ◽  
Heuristic Approach ◽  
Spiking Neural Networks ◽  
Grasshopper Optimization Algorithm ◽  
Selection Of

AbstractThe third type of neural network called spiking is developed due to a more accurate representation of neuronal activity in living organisms. Spiking neural networks have many different parameters that can be difficult to adjust manually to the current classification problem. The analysis and selection of coefficients’ values in the network can be analyzed as an optimization problem. A practical method for automatic selection of them can decrease the time needed to develop such a model. In this paper, we propose the use of a heuristic approach to analyze and select coefficients with the idea of collaborative working. The proposed idea is based on parallel analyzing of different coefficients and choosing the best of them or average ones. This type of optimization problem allows the selection of all variables, which can significantly affect the convergence of the accuracy. Our proposal was tested using network simulators and popular databases to indicate the possibilities of the described approach. Five different heuristic algorithms were tested and the best results were reached by Cuckoo Search Algorithm, Grasshopper Optimization Algorithm, and Polar Bears Algorithm.

A Sensitivity Based Heuristic for Optimal Blade Arrangement in a Linear Mistuned Rotor

2018 ◽  
Author(s):  
Mainak Mitra ◽  
Alparslan Emrah Bayrak ◽  
Stefano Zucca ◽  
Bogdan I. Epureanu
Keyword(s):  
Optimization Problem ◽  
Nonlinear Function ◽  
Heuristic Approach ◽  
Dynamic Responses ◽  
Order Model ◽  
Reduced Order ◽  
Bladed Disk ◽  
Rotor Design ◽  
Continuous Parameter ◽  
Response Amplification

This paper investigates methodologies for finding optimal or near-optimal blade arrangements in a bladed disk with inserted blades for minimizing or maximizing blade response amplification due to mistuning in material properties of the blades. The mistuning in the blades is considered to be known, and only their arrangement is modifiable. Hence, this is a problem in discrete optimization, particularly combinatorial optimization where the objective of response amplification is a nonlinear function of the blade arrangement. Previous studies have treated mistuning as a continuous parameter to analyze its effects on the response amplification. Sensitivity metrics have proven to be an important tool in quantifying the effects of mistuning. One such sensitivity metric is used here to formulate an iterative heuristic approach to solve the optimization problem. A component mode mistuning reduced order model is used for fast evaluations of the dynamic responses of a bladed disk with a given blade arrangement. At any iteration the sensitivity of the maximum response of the current rotor design to changes in blade stiffnesses due to changes in the blade arrangement is used to predict the arrangement for the following iteration. In addition to the proposed sensitivity-based approach, we use genetic algorithms to find optimal arrangements and compare results with the heuristic approach.

The Market for CSR Practices

2019 ◽  
pp. 173-186
Author(s):  
Irene Daskalopoulou
Keyword(s):  
Integrative Approach ◽  
Complex Nature ◽  
Food Sector ◽  
Market Outcomes ◽  
Demand And Supply ◽  
Critical Dimensions ◽  
The Way

The aim of the paper is to stimulate a discussion about the market for CSR practices. This entails a shift of focus from contemporary approaches of analyzing the phenomenon that largely focus on the way in which CSR actions affect businesses and the markets. In contrast, the present paper proposes an analysis of the market for CSR actions and activities as a more integrative approach to conceptualizing the complex nature of the phenomenon. Three critical dimensions are identified as determinants of CSR market outcomes, namely the content of the demand and supply forces, the origin of the market, and the institutional terrain within which the market is developed. A tentative application of the proposed context is discussed with reference to the food sector.

scholarly journals The Archaeology of Teaching: A Conceptual Framework

2015 ◽  
Vol 25 (4) ◽  
pp. 859-866 ◽  
Author(s):  
Francesco d'Errico ◽  
William E. Banks
Keyword(s):  
Conceptual Framework ◽  
Case Studies ◽  
Learning Strategies ◽  
Learning Processes ◽  
Heuristic Approach ◽  
Knowledge Transmission ◽  
Archaeological Record ◽  
Social Dimensions ◽  
Cumulative Culture ◽  
The Way

Studying the emergence of teaching in our lineage entails identifying learning strategies among human and non-human groups, understanding the situations in which they occur, evaluating their performance, recognizing their expression in the archaeological record, identifying trends in the way knowledge transmission changed through time, and detecting the key moments in which members of our lineage complemented pre-existing transmission strategies with those that led our species to develop cumulative culture and eventually ‘teaching’ as we know it. Here we explore how learning processes function in spatial, temporal, and social dimensions and use the resulting situations to build a tentative framework, which may guide our interpretation of the archaeological record and ultimately aid our identification of the learning processes at work in animal and past hominin societies. We test the pertinence of this heuristic approach by applying it to a handful of archaeological case studies.

The Market for CSR Practices

2016 ◽  
Vol 1 (1) ◽  
pp. 28-39
Author(s):  
Irene Daskalopoulou
Keyword(s):  
Integrative Approach ◽  
Complex Nature ◽  
Food Sector ◽  
Market Outcomes ◽  
Demand And Supply ◽  
Critical Dimensions ◽  
The Way

The aim of the paper is to stimulate a discussion about the market for CSR practices. This entails a shift of focus from contemporary approaches of analyzing the phenomenon that largely focus on the way in which CSR actions affect businesses and the markets. In contrast, the present paper proposes an analysis of the market for CSR actions and activities as a more integrative approach to conceptualizing the complex nature of the phenomenon. Three critical dimensions are identified as determinants of CSR market outcomes, namely the content of the demand and supply forces, the origin of the market, and the institutional terrain within which the market is developed. A tentative application of the proposed context is discussed with reference to the food sector.

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