Comparing Filtering Multifidelity Optimization Strategies With a Simulation-Based Multidisciplinary Aircraft Model

2021 ◽  
Vol 143 (8) ◽  
Author(s):  
Brian Chell ◽  
Steven Hoffenson ◽  
Cory J. G. Philippe ◽  
Mark R. Blackburn
Keyword(s):  
Multidisciplinary Optimization ◽  
High Fidelity ◽  
Element Analysis ◽  
Solution Quality ◽  
Local Algorithms ◽  
Starting Point ◽  
Aircraft System ◽  
Dynamics Simulations ◽  
The Impact ◽  
Multifidelity Optimization

Abstract Multifidelity optimization leverages the fast run times of low-fidelity models with the accuracy of high-fidelity models (HFMs), in order to conserve computing resources while still reaching optimal solutions. This work focuses on the multifidelity multidisciplinary optimization of an aircraft system model with finite element analysis and computational fluid dynamics simulations in the loop. A two-step filtering method is used where a lower fidelity model is optimized, and then the solution is used as a starting point for a higher-fidelity optimization routine. By starting the high-fidelity routine at a nearly optimal region of the design space, the computing resources required for optimization are expected to decrease when using local algorithms. Results show that, when using surrogates for the lower fidelity models, the multifidelity workflows save statistically significant amounts of time over optimizing the original HFM alone. However, the impact on solution quality varies depending on the model behavior and optimization algorithm.

Comparing Multifidelity Model Management Strategies for Multidisciplinary Design Optimization

2019 ◽  
Author(s):  
Brian Chell ◽  
Steven Hoffenson ◽  
Mark R. Blackburn
Keyword(s):  
Management Strategies ◽  
Model Management ◽  
High Fidelity ◽  
Element Analysis ◽  
Starting Point ◽  
Optimal Section ◽  
Gradient Based ◽  
Optimization Routine ◽  
Dynamics Simulations ◽  
Multifidelity Optimization

Abstract Multifidelity optimization leverages the fast run times of low-fidelity models with the accuracy of high-fidelity models, in order to conserve computing resources while still reaching optimal solutions. This work focuses on the multidisciplinary multifidelity optimization of an unmanned aerial system model with finite element analysis and computational fluid dynamics simulations in-the-loop. A two-step process is used where the lower-fidelity models are optimized, and then the optimizer is used as a starting point for the higher-fidelity models. By starting the high-fidelity optimization routine at a nearly optimal section of the design space, the computing resources required for optimization are expected to decrease when using gradient-based algorithms. Results show that, at least in some cases, the multifidelity workflows save time over optimizing the original high fidelity model alone. However, the model management strategy did not find statistically significant differences between the differing optimization approaches when used on this test problem.

Impact of Including Electronics Design on Design of Intelligent Structures: Applications to Multifunctional Structures for Attitude Control (MSAC)

2020 ◽  
Author(s):  
Vedant ◽  
James T. Allison
Keyword(s):  
Control System ◽  
Power Electronics ◽  
Attitude Control ◽  
Dynamic Models ◽  
High Fidelity ◽  
Element Analysis ◽  
Design Studies ◽  
Intelligent Structures ◽  
The Impact ◽  
Electronics Design

Abstract Multifunctional Structures for Attitude Control (MSAC) is a new spacecraft attitude control system that utilizes deployable panels as multifunctional intelligent structures to provide both fine pointing and large slew attitude control. Previous studies introduced MSAC design and operation concepts, simulation-based design studies, and Hardware-in-the-Loop (HIL) validation of a simplified prototype. In this article, we expand the scope of design studies to include individual compliant piezo-electric actuators and associated power electronics. This advance is a step toward high-fidelity MSAC system operation, and reveals new design insights for further performance enhancement. Actuators are designed using pseudo rigid body dynamic models (PRBDMs), and are validated for steady-state and step responses against Finite Element Analysis. The drive electronics model consists of a few distinct topologies that will be used to evaluate system performance for given mechanical and control system designs. Subsequently, a high-fidelity multiphysics multibody MSAC system model, based on the validated compliant actuators and drive electronics, is developed to support implementation of MSAC Control Co-design optimization studies. This model will be used to demonstrate the impact of including the power electronics design in the Optimal Control Co-Design domain. The different control trajectories are compared for slew rates and the vibrational jitter introduced to the satellite. The results from this work will be used to realize closed-loop control trajectories that have minimal jitter introduction while providing high slew rates.

Liszt at the Piano: The Impact of Iconography on mid-Nineteenth Century Musicology

2014 ◽  
Vol 55 (1-2) ◽  
pp. 131-144
Author(s):  
Suzanne Marie Francis
Keyword(s):  
Nineteenth Century ◽  
Music History ◽  
Collective Identities ◽  
Cultural Contexts ◽  
Maximum Benefit ◽  
Starting Point ◽  
The Social ◽  
Iconic Status ◽  
The Impact

By the time of his death in 1827, the image of Beethoven as we recognise him today was firmly fixed in the minds of his contemporaries, and the career of Liszt was beginning to flower into that of the virtuosic performer he would be recognised as by the end of the 1830s. By analysing the seminal artwork Liszt at the Piano of 1840 by Josef Danhauser, we can see how a seemingly unremarkable head-and-shoulders bust of Beethoven in fact holds the key to unlocking the layers of commentary on both Liszt and Beethoven beneath the surface of the image. Taking the analysis by Alessandra Comini as a starting point, this paper will look deeper into the subtle connections discernible between the protagonists of the picture. These reveal how the collective identities of the artist and his painted assembly contribute directly to Beethoven’s already iconic status within music history around 1840 and reflect the reception of Liszt at this time. Set against the background of Romanticism predominant in the social and cultural contexts of the mid 1800s, it becomes apparent that it is no longer enough to look at a picture of a composer or performer in isolation to understand its impact on the construction of an overall identity. Each image must be viewed in relation to those that preceded and came after it to gain the maximum benefit from what it can tell us.

Nachhaltigkeit im Wald – vor und hinter der Welle der Globalisierung | Sustainable Forest Management – In Front and Behind the Wave of Globalization

2000 ◽  
Vol 151 (12) ◽  
pp. 502-507
Author(s):  
Christian Küchli
Keyword(s):  
Forest Management ◽  
Cultural Landscape ◽  
Sustainable Forest Management ◽  
Essential Element ◽  
Specific Situation ◽  
The South ◽  
The North ◽  
Time Space ◽  
Starting Point ◽  
The Impact

Are there any common patterns in the transition processes from traditional and more or less sustainable forest management to exploitative use, which can regularly be observed both in central Europe and in the countries of the South (e.g. India or Indonesia)? Attempts were made with a time-space-model to typify those force fields, in which traditional sustainable forest management is undermined and is then transformed into a modern type of sustainable forest management. Although it is unlikely that the history of the North will become the future of the South, the glimpse into the northern past offers a useful starting point for the understanding of the current situation in the South, which in turn could stimulate the debate on development. For instance, the patterns which stand behind the conflicts on forest use in the Himalayas are very similar to the conflicts in the Alps. In the same way, the impact of socio-economic changes on the environment – key word ‹globalisation› – is often much the same. To recognize comparable patterns can be very valuable because it can act as a stimulant for the search of political, legal and technical solutions adapted to a specific situation. For the global community the realization of the way political-economic alliances work at the head of the ‹globalisationwave›can only signify to carry on trying to find a common language and understanding at the negotiation tables. On the lee side of the destructive breaker it is necessary to conserve and care for what survived. As it was the case in Switzerland these forest islands could once become the germination points for the genesis of a cultural landscape, where close-to-nature managed forests will constitute an essential element.

Design of Inhibitors for Glyceraldehyde-3-phosphate Dehydrogenase (GAPDH) Enzyme of Leishmania mexicana

2020 ◽  
Vol 16 (6) ◽  
pp. 784-795
Author(s):  
Krisnna M.A. Alves ◽  
Fábio José Bonfim Cardoso ◽  
Kathia M. Honorio ◽  
Fábio A. de Molfetta
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Binding Site ◽  
Point Of View ◽  
New Drugs ◽  
Leishmania Mexicana ◽  
Receptor Complexes ◽  
Starting Point ◽  
Dynamics Simulations ◽  
Selection Of

Background:: Leishmaniosis is a neglected tropical disease and glyceraldehyde 3- phosphate dehydrogenase (GAPDH) is a key enzyme in the design of new drugs to fight this disease. Objective:: The present study aimed to evaluate potential inhibitors of GAPDH enzyme found in Leishmania mexicana (L. mexicana). Methods: A search for novel antileishmanial molecules was carried out based on similarities from the pharmacophoric point of view related to the binding site of the crystallographic enzyme using the ZINCPharmer server. The molecules selected in this screening were subjected to molecular docking and molecular dynamics simulations. Results:: Consensual analysis of the docking energy values was performed, resulting in the selection of ten compounds. These ligand-receptor complexes were visually inspected in order to analyze the main interactions and subjected to toxicophoric evaluation, culminating in the selection of three compounds, which were subsequently submitted to molecular dynamics simulations. The docking results showed that the selected compounds interacted with GAPDH from L. mexicana, especially by hydrogen bonds with Cys166, Arg249, His194, Thr167, and Thr226. From the results obtained from molecular dynamics, it was observed that one of the loop regions, corresponding to the residues 195-222, can be related to the fitting of the substrate at the binding site, assisting in the positioning and the molecular recognition via residues responsible for the catalytic activity. Conclusion:: he use of molecular modeling techniques enabled the identification of promising compounds as inhibitors of the GAPDH enzyme from L. mexicana, and the results obtained here can serve as a starting point to design new and more effective compounds than those currently available.

Law and Economics

2020 ◽  
pp. 84-102
Author(s):  
Daniel B. Kelly
Keyword(s):  
Economic Analysis ◽  
First Generation ◽  
Law And Economics ◽  
Private Law ◽  
Foreseeable Future ◽  
Business Associations ◽  
The Third ◽  
Starting Point ◽  
The Law ◽  
The Impact

This chapter analyzes how law and economics influences private law and how (new) private law is influencing law and economics. It focuses on three generation or “waves” within law and economics and how they approach private law. In the first generation, many scholars took the law as a starting point and attempted to use economic insights to explain, justify, or reform legal doctrines, institutions, and structures. In the second generation, the “law” at times became secondary, with more focus on theory and less focus on doctrines, institutions, and structures. But this generation also relied increasingly on empirical analysis. In the third generation, which includes scholars in the New Private Law (NPL), there has been a resurgence of interest in the law and legal institutions. To be sure, NPL scholars analyze the law using various approaches, with some more and some less predisposed to economic analysis. However, economic analysis will continue to be a major force on private law, including the New Private Law, for the foreseeable future. The chapter considers three foundational private law areas: property, contracts, and torts. For each area, it discusses the major ideas that economic analysis has contributed to private law, and surveys contributions of the NPL. The chapter also looks at the impact of law and economics on advanced private law areas, such as business associations, trusts and estates, and intellectual property.

scholarly journals Potential and limitations of finite element modelling in assessing structural integrity of coralline algae under future global change

2015 ◽  
Vol 12 (19) ◽  
pp. 5871-5883 ◽  
Author(s):  
L. A. Melbourne ◽  
J. Griffin ◽  
D. N. Schmidt ◽  
E. J. Rayfield
Keyword(s):  
Climate Change ◽  
Finite Element ◽  
Structural Integrity ◽  
Geometric Model ◽  
Algal Growth ◽  
Coralline Algae ◽  
Rocky Shores ◽  
Element Analysis ◽  
Scan Data ◽  
The Impact

Abstract. Coralline algae are important habitat formers found on all rocky shores. While the impact of future ocean acidification on the physiological performance of the species has been well studied, little research has focused on potential changes in structural integrity in response to climate change. A previous study using 2-D Finite Element Analysis (FEA) suggested increased vulnerability to fracture (by wave action or boring) in algae grown under high CO2 conditions. To assess how realistically 2-D simplified models represent structural performance, a series of increasingly biologically accurate 3-D FE models that represent different aspects of coralline algal growth were developed. Simplified geometric 3-D models of the genus Lithothamnion were compared to models created from computed tomography (CT) scan data of the same genus. The biologically accurate model and the simplified geometric model representing individual cells had similar average stresses and stress distributions, emphasising the importance of the cell walls in dissipating the stress throughout the structure. In contrast models without the accurate representation of the cell geometry resulted in larger stress and strain results. Our more complex 3-D model reiterated the potential of climate change to diminish the structural integrity of the organism. This suggests that under future environmental conditions the weakening of the coralline algal skeleton along with increased external pressures (wave and bioerosion) may negatively influence the ability for coralline algae to maintain a habitat able to sustain high levels of biodiversity.

Impact Load Buffering Method Based on Stress Wave Attenuation Principle

2019 ◽  
Vol 11 (02) ◽  
pp. 1950019 ◽  
Author(s):  
Lin Gan ◽  
He Zhang ◽  
Cheng Zhou ◽  
Lin Liu
Keyword(s):  
Stress Wave ◽  
Wave Attenuation ◽  
Impact Load ◽  
Dynamics Simulation ◽  
Scanning System ◽  
Isolation Method ◽  
Element Analysis ◽  
System A ◽  
High Emission ◽  
The Impact

Rotating scanning motor is the important component of synchronous scanning laser fuze. High emission overload environment in the conventional ammunition has a serious impact on the reliability of the motor. Based on the theory that the buffer pad can attenuate the impact stress wave, a new motor buffering Isolation Method is proposed. The dynamical model of the new buffering isolation structure is established by ANSYS infinite element analysis software to do the nonlinear impact dynamics simulation of rotating scanning motor. The effectiveness of Buffering Isolation using different materials is comparatively analyzed. Finally, the Macht hammer impact experiment is done, the results show that in the experience of the 70,000[Formula: see text]g impact acceleration, the new buffering Isolation method can reduce the impact load about 15 times, which can effectively alleviate the plastic deformation of rotational scanning motor and improve the reliability of synchronization scanning system. A new method and theoretical basis of anti-high overload research for Laser Fuze is presented.

Engels on women, the family, class and gender

2021 ◽  
pp. 194277862110000
Author(s):  
Sheila Margaret McGregor
Keyword(s):  
Historical Materialism ◽  
Human Society ◽  
Human Beings ◽  
True Nature ◽  
Starting Point ◽  
Women's Oppression ◽  
1960S And 1970S ◽  
Socialist Movement ◽  
The Impact ◽  
The Way

This article looks at Engels’s writings to show that his ideas about the role of labour in the evolution of human beings in a dialectical relationship between human beings and nature is a crucial starting point for understanding human society and is correct in its essentials. It is important for understanding that we developed as a species on the basis of social cooperation. The way human beings produce and reproduce themselves, the method of historical materialism, provides the basis for understanding how class and women’s oppression arose and how that can explain LGBTQ oppression. Although Engels’s analysis was once widely accepted by the socialist movement, it has mainly been ignored or opposed by academic researchers and others, including geographers, and more recently by Marxist feminists. However, anthropological research from the 1960s and 1970s as well as more recent anthropological and archaeological research provide overwhelming evidence for the validity of Engels’s argument that there were egalitarian, pre-class societies without women’s oppression. However, much remains to be explained about the transition to class societies. Engels’s analysis of the impact of industrial capitalism on gender roles shows how society shapes our behaviour. Engels’s method needs to be constantly reasserted against those who would argue that we are a competitive, aggressive species who require rules to suppress our true nature, and that social development is driven by ideas, not by changes in the way we produce and reproduce ourselves.

scholarly journals On Present Value Evaluation under the Impact of Behavioural Factors Using Oriented Fuzzy Numbers

Symmetry ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 468
Author(s):  
Krzysztof Piasecki ◽  
Anna Łyczkowska-Hanćkowiak
Keyword(s):  
Fuzzy Numbers ◽  
Asset Price ◽  
Financial Knowledge ◽  
Present Value ◽  
Market Knowledge ◽  
Value Evaluation ◽  
Starting Point ◽  
Behavioural Factors ◽  
Objective Financial Knowledge ◽  
The Impact

In general, the present value (PV) concept is ambiguous. Therefore, behavioural factors may influence on the PV evaluation. The main aim of our paper is to propose some method of soft computing PV evaluated under the impact of behavioural factors. The starting point for our discussion is the notion of the Behavioural PV (BPV) defined as an imprecisely real-valued function of distinguished variables which can be evaluated using objective financial knowledge or subjective behavioural premises. In our paper, a BPV is supplemented with a forecast of the asset price closest to changes. Such BPV is called the oriented BPV (O-BPV). We propose to evaluate an O-BPV by oriented fuzzy numbers which are more useful for portfolio analysis than fuzzy numbers. This fact determines the significance of the research described in this article. O-BPV may be applied as input signal for systems supporting invest-making. We consider here six cases of O-BPV: overvalued asset with the prediction of a rise in its price, overvalued asset with the prediction of a fall in its price, undervalued asset with the prediction of a rise in its price, undervalued asset with the prediction of a fall in its price, fully valued asset with the prediction of a rise in its rice and fully valued asset with the prediction of a fall in its rice. All our considerations are illustrated by numerical examples. Presented examples show the way in which we transform superposition of objective market knowledge and subjective investment opinion into simple return rate.

Sign in / Sign up

Export Citation Format

Share Document