An Efficient Weighting Update Method to Achieve Acceptable Consistency Deviation in Analytical Target Cascading

2005 ◽  
Vol 127 (2) ◽  
pp. 206-214 ◽  
Author(s):  
Jeremy J. Michalek ◽  
Panos Y. Papalambros
Keyword(s):  
Computational Time ◽  
Relative Importance ◽  
Analytical Target Cascading ◽  
Proper Selection ◽  
Target Cascading ◽  
Stretch Targets ◽  
Design Consistency ◽  
Weighting Coefficients ◽  
Acceptable Consistency ◽  
Selection Of

Weighting coefficients are used in analytical target cascading (ATC) at each element of the hierarchy to express the relative importance of (a) matching targets passed from the parent element and (b) maintaining consistency of linking variables and consistency with designs achieved by subsystem child elements. Proper selection of weight values is crucial when the top-level targets are unattainable, for example when “stretch” targets are used. In this case, strict design consistency cannot be achieved with finite weights; however, it is possible to achieve arbitrarily small inconsistencies. This article presents an iterative method for finding weighting coefficients that achieve solutions within user-specified inconsistency tolerances and demonstrates its effectiveness with several examples. The method also led to reduced computational time in the demonstration examples.

An Efficient Weighting Update Method to Achieve Acceptable Consistency Deviation in Analytical Target Cascading

2004 ◽  
Author(s):  
Jeremy J. Michalek ◽  
Panos Y. Papalambros
Keyword(s):  
Computational Time ◽  
Relative Importance ◽  
Analytical Target Cascading ◽  
Proper Selection ◽  
Target Cascading ◽  
Stretch Targets ◽  
Design Consistency ◽  
Weighting Coefficients ◽  
Acceptable Consistency ◽  
Selection Of

Weighting coefficients are used in Analytical Target Cascading (ATC) at each element of the hierarchy to express the relative importance of matching targets passed from the parent element and maintaining consistency of linking variables and consistency with designs achieved by subsystem child elements. Proper selection of weight values is crucial when the top level targets are unattainable, for example when “stretch” targets are used. In this case, strict design consistency cannot be achieved with finite weights; however, it is possible to achieve arbitrarily small inconsistencies. This article presents an iterative method for finding weighting coefficients that achieve solutions within user-specified inconsistency tolerances and demonstrates its effectiveness with several examples. The method also led to reduced computational time in the demonstration examples.

Probabilistic Analytical Target Cascading: A Moment Matching Formulation for Multilevel Optimization Under Uncertainty

2005 ◽  
Author(s):  
Huibin Liu ◽  
Wei Chen ◽  
Michael Kokkolaras ◽  
Panos Y. Papalambros ◽  
Harrison M. Kim
Keyword(s):  
Probabilistic Approach ◽  
Optimization Under Uncertainty ◽  
Analytical Target Cascading ◽  
Multilevel Optimization ◽  
Coordination Strategies ◽  
Simulation Based ◽  
Target Cascading ◽  
Design Consistency ◽  
System Design Optimization ◽  
Probabilistic Analytical Target Cascading

Analytical target cascading (ATC) is a methodology for hierarchical multilevel system design optimization. In previous work, the deterministic ATC formulation was extended to account for uncertainties using a probabilistic approach. Random quantities were represented by their expected values, which were required to match among subproblems to ensure design consistency. In this work, the probabilistic formulation is augmented to allow introduction and matching of additional probabilistic characteristics. Applying robust design principles, a particular probabilistic analytic target cascading (PATC) formulation is proposed by matching the first two moments of random quantities. Several implementation issues are addressed, including representation of probabilistic design targets, matching interrelated responses and linking variables under uncertainty, and coordination strategies for multilevel optimization. Analytical and simulation-based optimal design examples are used to illustrate the new PATC formulation. Design consistency is achieved by matching the first two moments of interrelated responses and linking variables. The effectiveness of the approach is demonstrated by comparing PATC results to those obtained using a probabilistic all-in-one (PAIO) formulation.

Bounded Target Cascading in Hierarchical Design Optimization

2011 ◽  
Author(s):  
Xiao-Ling Zhang ◽  
Po Ting Lin ◽  
Hae Chang Gea ◽  
Hong-Zhong Huang
Keyword(s):  
Design Optimization ◽  
Optimization Problems ◽  
System Level ◽  
Weighted Sum ◽  
Analytical Target Cascading ◽  
Hierarchical Design ◽  
Design Variables ◽  
Target Cascading ◽  
The Cost ◽  
Weighting Coefficients

Analytical Target Cascading method has been widely developed to solve hierarchical design optimization problems. In the Analytical Target Cascading method, a weighted-sum formulation has been commonly used to coordinate the inconsistency between design points and assigned targets in each level while minimizing the cost function. However, the choice of the weighting coefficients is very problem dependent and improper selections of the weights will lead to incorrect solutions. To avoid the problems associated with the weights, single objective functions in the hierarchical design optimization are formulated by a new Bounded Target Cascading method. Instead of point targets assigned for design variables in the Analytical Target Cascading method, bounded targets are introduced in the new method. The target bounds are obtained from the optimal solutions in each level while the response bounds are updated back to the system level. If the common variables exist, they are coordinated based on their sensitivities with respect to design variables. Finally, comparisons of the results from the proposed method and the weighted-sum Analytical Target Cascading are presented and discussed.

Meriel Talbot and the Society for the Overseas Settlement of British Women, 1919–1937

2017 ◽  
Vol 10 (1) ◽  
pp. 32-52
Author(s):  
Bonnie White
Keyword(s):  
Domestic Service ◽  
Agricultural Workers ◽  
British Government ◽  
Early Failure ◽  
Proper Selection ◽  
Domestic Servants ◽  
Female Workers ◽  
Female Migrants ◽  
Post War ◽  
Selection Of

In 1917 the British government began making plans for post-war adjustments to the economy, which included the migration of surplus women to the dominions. The Society for the Overseas Settlement of British Women was established in 1920 to facilitate the migration of female workers to the dominions. Earlier studies have argued that overseas emigration efforts purposefully directed women into domestic service as surplus commodities, thus alleviating the female ‘surplus’ and easing economic hardships of the post-war period. This article argues that as Publicity Officer for the SOSBW, Meriel Talbot targeted women she believed would be ideal candidates for emigration, including former members of the Women's Land Army and affiliated groups. With the proper selection of female migrants, Talbot sought to expand work opportunities for women in the dominions beyond domestic service, while reducing the female surplus at home and servicing the connection between state and empire. Dominion authorities, whose demands for migrant labour vacillated between agricultural workers during the war years and domestic servants after 1920, disapproved of Talbot's efforts to migrate women for work in agriculture. Divergent policies led to the early failure of the SOSBW in 1923.

Is Hydraulics Over-Used or Under-Used in Storm Drainage?

1994 ◽  
Vol 29 (1-2) ◽  
pp. 53-61
Author(s):  
Ben Chie Yen
Keyword(s):  
Unsteady Flow ◽  
Computational Time ◽  
Time Step ◽  
Flow Routing ◽  
Kinematic Wave Equation ◽  
Storm Drainage ◽  
Saint Venant Equations ◽  
Unsteady Flow Routing ◽  
Selection Of

Urban drainage models utilize hydraulics of different levels. Developing or selecting a model appropriate to a particular project is not an easy task. Not knowing the hydraulic principles and numerical techniques used in an existing model, users often misuse and abuse the model. Hydraulically, the use of the Saint-Venant equations is not always necessary. In many cases the kinematic wave equation is inadequate because of the backwater effect, whereas in designing sewers, often Manning's formula is adequate. The flow travel time provides a guide in selecting the computational time step At, which in turn, together with flow unsteadiness, helps in the selection of steady or unsteady flow routing. Often the noninertia model is the appropriate model for unsteady flow routing, whereas delivery curves are very useful for stepwise steady nonuniform flow routing and for determination of channel capacity.

scholarly journals Design Concepts for NiTiNOL Wires to Function as a Sensor

2021 ◽  
Author(s):  
D. Josephine Selvarani Ruth
Keyword(s):  
Shape Memory Alloy ◽  
Electrical Resistance ◽  
Nickel Titanium ◽  
The Other ◽  
Sensing Element ◽  
Proper Selection ◽  
Design Concepts ◽  
Mechanical Element ◽  
Selection Of ◽  
Inverse Hysteresis

AbstractNickel Titanium Naval Ordinance Laboratory (NiTiNOL) is widely called as a shape memory alloy (SMA), a class of nonlinear smart material inherited with the functionally programmed property of varying electrical resistance during the transformation enabling to be positioned as a sensing element. The major challenge to instrument the SMA wires is to suppress the wires’ nonlinearity by proper selection of two important factors. The first factor is influenced by the mechanical biasing element and the other is to identify the sensing current for the sensing device (SMA wires + biasing). This paper focuses on developing SMA wires for sensing in different orientation types and configurations by removing the non-linearity in the system’s output by introducing inverse hysteresis to the wires through the passive mechanical element.

A Non-Normality Measure of the Condition Number for Monitoring and Control

1997 ◽  
Vol 119 (2) ◽  
pp. 217-222 ◽  
Author(s):  
Kunsoo Huh ◽  
Jeffrey L. Stein
Keyword(s):  
Optimal Control ◽  
Condition Number ◽  
Minimization Problem ◽  
Monitoring And Control ◽  
Proper Selection ◽  
Modal Structure ◽  
L2 Norm ◽  
And Control ◽  
Normality Measure ◽  
Selection Of

Because the behavior of the condition number can have highly steep and multi-modal structure, optimal control and monitoring problems based on the condition number cannot be easily solved. In this paper, a minimization problem is formulated for κ2(P), the condition number of an eigensystem (P) of a matrix in terms of the L2 norm. A new non-normality measure is shown to exist that guarantees small values for the condition number. In addition, this measure can be minimized by proper selection of controller and observer gains. Application to the design of well-conditioned controller and observer-based monitors is illustrated.

scholarly journals Influence of the Chemical Composition on Electrical Conductivity and Mechanical Properties of the Hypoeutectic Al-Si-Mg Alloys

2016 ◽  
Vol 61 (1) ◽  
pp. 353-360 ◽  
Author(s):  
B. Dybowski ◽  
J. Szymszal ◽  
Ł. Poloczek ◽  
A. Kiełbus
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Chemical Composition ◽  
Aluminium Alloys ◽  
Mg Alloys ◽  
High Electrical Conductivity ◽  
Transportation Industry ◽  
Proper Selection ◽  
Ti Addition ◽  
Selection Of

Due to low density and good mechanical properties, aluminium alloys are widely applied in transportation industry. Moreover, they are characterized by the specific physical properties, such as high electrical conductivity. This led to application of the hypoeutectic Al-Si-Mg alloys in the power generation industry. Proper selection of the alloys chemical composition is an important stage in achievement of the demanded properties. The following paper presents results of the research on the influence of alloys chemical composition on their properties. It has been revealed that Si and Ti addition decreases electrical conductivity of the Al-Si-Mg alloys, while Na addition increases it. The mechanical properties of the investigated alloys are decreased by both silicon and iron presence. Sodium addition increases ductility of the Al-Si-Mg alloys.

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