scholarly journals Automated Design of CubeSats using Evolutionary Algorithm for Trade Space Selection

Aerospace ◽  
2020 ◽  
Vol 7 (10) ◽  
pp. 142
Author(s):  
Himangshu Kalita ◽  
Jekan Thangavelautham
Keyword(s):  
Automated Design ◽  
Earth Observation ◽  
Design Team ◽  
Optimal Solutions ◽  
Sensors And Actuators ◽  
Spacecraft Design ◽  
Alternative Approach ◽  
Starting Point ◽  
Interplanetary Missions ◽  
Mass Volume

The miniaturization of electronics, sensors, and actuators has enabled the growing use of nanosatellites for earth observation, astrophysics, and even interplanetary missions. This rise of nanosatellites has led to the development of an inventory of modular, interchangeable commercially-off-the-shelf (COTS) components by a multitude of commercial vendors. As a result, the capability of combining subsystems in a compact platform has considerably advanced in the last decade. However, to ascertain these spacecraft’s maximum capabilities in terms of mass, volume, and power, there is an important need to optimize their design. Current spacecraft design methods need engineering experience and judgements made by of a team of experts, which can be labor intensive and might lead to a sub-optimal design. In this work we present a compelling alternative approach using machine learning to identify near-optimal solutions to extend the capabilities of a design team. The approach enables automated design of a spacecraft that requires developing a virtual warehouse of components and specifying quantitative goals to produce a candidate design. The near-optimal solutions found through this approach would be a credible starting point for the design team that will need further study to determine their implementation feasibility.

scholarly journals Layout optimization of simplified trusses using mixed integer linear programming with runtime generation of constraints

2020 ◽  
Vol 61 (5) ◽  
pp. 1977-1999
Author(s):  
H. Fairclough ◽  
M. Gilbert
Keyword(s):  
Linear Programming ◽  
Integer Linear Programming ◽  
Mixed Integer Linear Programming ◽  
Geometry Optimization ◽  
Layout Optimization ◽  
Mixed Integer ◽  
Optimal Solutions ◽  
Problem Size ◽  
Solution Quality ◽  
Starting Point

AbstractTraditional truss layout optimization employing the ground structure method will often generate layouts that are too complex to fabricate in practice. To address this, mixed integer linear programming can be used to enforce buildability constraints, leading to simplified truss forms. Limits on the number of joints in the structure and/or the minimum angle between connected members can be imposed, with the joints arising from crossover of pairs of members accounted for. However, in layout optimization, the number of constraints arising from ‘crossover joints’ increases rapidly with problem size, along with computational expense. To address this, crossover constraints are here dynamically generated and added at runtime only as required (so-called lazy constraints); speedups of more than 20 times are observed whilst ensuring that there is no loss of solution quality. Also, results from the layout optimization step are shown to provide a suitable starting point for a non-linear geometry optimization step, enabling results to be obtained that are in agreement with literature solutions. It is also shown that symmetric problems may not have symmetric optimal solutions, and that multiple distinct and equally optimal solutions may be found.

Error management: implications for construction

2016 ◽  
Vol 16 (4) ◽  
pp. 418-424 ◽  
Author(s):  
Peter E.D. Love ◽  
Jim Smith
Keyword(s):  
Design Methodology ◽  
Shared Responsibility ◽  
Error Reporting ◽  
Future Research ◽  
Error Management ◽  
Learning From Errors ◽  
Content Type ◽  
Alternative Approach ◽  
Starting Point ◽  
Initial Starting

Purpose Conventional “wisdom” in construction has placed emphasis on error prevention and is often aligned with the concept of “Zero Vision”; improvements to safety and quality have been minimal. An alternative approach is needed to ensure significant improvements in safety and quality; thus, this paper aims to introduce the concept of error management. Design/methodology/approach The paper reviews the extant literature and draws upon the phenomenological research and observations experienced by the authors. Findings It is promulgated that if quality and safety performance within projects is to improve, then construction organisations and their management need to openly acknowledge their presence so that “learning from errors” can form an integral part of an organisation’s fabric. This will require the institutionalisation of error reporting and an organisational (shared) responsibility for their occurrence. Originality/value The concept of error management has not been addressed previously in the construction literature. The authors introduce the concept and provide implications for management. The observations and experiences presented in this paper provide an initial starting point for future research to explore “how” construction organisations and projects can avoid the negative error consequences and learn to prevent them in the future.

scholarly journals Time-Mean Helicity Distribution in Turbulent Swirling Jets

10.14311/776 ◽  
2005 ◽  
Vol 45 (6) ◽  
Author(s):  
V. Tesař
Keyword(s):  
Spatial Distribution ◽  
Turbulent Flows ◽  
Large Time ◽  
Small Region ◽  
Density Profiles ◽  
Swirling Jets ◽  
Helicity Distribution ◽  
Alternative Approach ◽  
Starting Point ◽  
The Subject

Helicity offers an alternative approach to investigations of the structure of turbulent flows. Knowledge of the spatial distribution of the time-mean component of helicity is the starting point. Yet very little is known even about basic cases in which Helicity plays important role, such as the case of a swirling jet. This is the subject of the present investigations, based mainly on numerical flowfield computations. The region of significantly large time-mean helicity density is found only in a rather small region reaching to several nozzle diameters downstream from the exit. The most important result is the similarity of the helicity density profiles. 

scholarly journals Histórias de Homero: um Balanço das Propostas de Datação dos Poemas Homéricos * Homer’s Histories: a Balance of the Dating Proposals of Homeric Poems

2013 ◽  
Vol 1 (2) ◽  
pp. 126
Author(s):  
GUSTAVO OLIVEIRA
Keyword(s):  
Oral Tradition ◽  
Historical Sources ◽  
Alternative Approach ◽  
Starting Point ◽  
Greek Epic

<p><strong>Resumo:</strong> A datação dos poemas homéricos é um assunto polêmico e repleto de dificuldades. Mesmo diante de tal cenário, sua utilização como fonte histórica tem ocorrido, em geral sem maiores considerações acerca da dificuldade de resolver problemas centrais para a maneira de como os poemas são contextualizados. O presente estudo tem como objetivo fazer um levantamento das possibilidades de abordagens históricas destes poemas, apontando as particularidades, os pressupostos e problemas relacionados a cada uma. Por fim é apresentada uma sugestão alternativa de abordagem, que toma como ponto de partida a datação da tradição da qual os poemas fazem parte, encarando-os como testemunhos válidos desta tradição de longa duração oral.</p><p><strong>Palavras-chave:</strong> Sociedade Homérica – Épica Grega – Tradição Oral.</p><p> </p><p><strong>Abstract:</strong> Dating the Homeric poems is a polemic subject, filled with difficulties. Even so, the poems have been used as historical sources, generally without any significant remarks about the difficulty in solving main problems in how the poems are put into context. The focus of this paper is to trace the possibilities of historical approaches which use the Homeric poems as sources and pointing out the particularities, the assumption and the problems presented in each type of approach. At last, it is suggested an alternative approach which has, as the starting point, the dating of  the tradition to which the poems belong, considering them valid testimonies of such a long-lasting oral tradition.</p><p><strong>Keywords:</strong> Homeric Society – Greek Epic – Oral Tradition.</p>

scholarly journals Models and Design Judgment: Conflicting Perspectives on Redesigning a Doctoral Readings Course

2012 ◽  
Vol 3 (1) ◽  
Author(s):  
Colin M. Gray ◽  
Jiyoon Jung ◽  
Carol Watson ◽  
Xiaokai Jia ◽  
Theodore W. Frick
Keyword(s):  
Design Process ◽  
Doctoral Program ◽  
Design Team ◽  
Online Environment ◽  
Course Structure ◽  
Iterative Design ◽  
Starting Point ◽  
Final Design ◽  
Strategic Goals ◽  
Potential Methods

The purpose of this project was to document the redesign of an existing doctoral reading course for an online environment. Potential methods for actualizing the proposed course structure in an online environment, including technology tools and interactions are discussed. The design process began within the framework of the Four-Component Instructional Design (4C/ID) model (van Merriënboer, 1997; van Merriënboer & Kirchner, 2007), which advocates a shift from topic-centeredness to a task-centered course organization, but quickly evolved into a flexible, iterative design process that was informed by prototyping, the judgment of the design team, and various theories of knowledge and knowing. The 4C/ID model represented our philosophical starting point, but our focus quickly shifted to a more flexible, eclectic process as we attempted to reconcile conflicting constraints on the final design. Along with the redevelopment of course objectives to meet strategic goals within the doctoral program came a focus on facilitating research thinking of the students rather than teaching isolated research tasks. The design process resulted in changes to the current residential course, which then provided an opportunity for further investigation. 

Intelligent intraoral drug delivery microsystem

2006 ◽  
Vol 220 (11) ◽  
pp. 1609-1617 ◽  
Author(s):  
T Velten ◽  
H Schuck ◽  
T Knoll ◽  
O Scholz ◽  
A Schumacher ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Remote Control ◽  
Release Mechanism ◽  
Patient Needs ◽  
Sensors And Actuators ◽  
Alternative Approach ◽  
System Components ◽  
Component Development ◽  
Small Channels ◽  
Microfluidic Component

The authors report on the concept and development of an intelligent intraoral drug delivery microsystem, that provides an alternative approach for the treatment of addiction and chronic diseases. The drug delivery system (DDS) comprises a medication replacement reservoir, a medication release mechanism, a built-in intelligence, a remote control, microsensors, and microactuators. It is thus able to release the medication in a controlled manner according to the patient needs. The emphasis of this article is on the application of sensors and microfluidic components in a real microsystem and also showing some details of two system components, namely, the osmotic pump and the flow sensor. The motivation for the microfluidic approach, the concept of the DDS, the requirements for this specific application, and the arising problems will be presented and discussed. Regarding the sensors and actuators, the problems mainly concern size and power consumption. A major challenging aspect of microfluidic component development is to avoid clogging of small channels because of particles and recrystallization of saturated fluids.

Extractivism or specificity of capital accumulation? A critique on the extractivist approach regarding the case of Argentina

2021 ◽  
pp. 030981682110174
Author(s):  
Nicolás Pérez Trento
Keyword(s):  
Latin American ◽  
Critical Analysis ◽  
Capital Accumulation ◽  
Theoretical Perspective ◽  
Explanatory Power ◽  
Development Model ◽  
Political Transformations ◽  
Alternative Approach ◽  
Starting Point ◽  
Latin American Countries

The recent economic and political transformations in many Latin American countries have been increasingly analysed under the (neo-)extractivism approach. Specifically, the debate surrounding the contradictions and limitations of this development model, as well as its consequences, gained traction among scholars. In this article, we intend to put forth a critical analysis of this approach with the goal of giving an account of its explanatory power, focusing on Argentina. In order to do this, we summarize some of the more noteworthy conceptual features of (neo-)extractivism, as well as the main arguments to include Argentina as a case. Then, after presenting some immediate conceptual limitations linked to this theoretical perspective, we introduce an alternative approach in regard to the specific way in which capital accumulation takes place in Argentina, based on the Critique of Political Economy put forward by Marx in Capital, and taking the global unity of capital accumulation as a starting point. This allows us to critically engage, in the last section, with the main claims of extractivism.

Corruption: An Alternative Approach to its Definition and Measurement

2005 ◽  
Vol 53 (1) ◽  
pp. 222-239 ◽  
Author(s):  
Oskar Kurer
Keyword(s):  
Political Process ◽  
Central Element ◽  
Public Office ◽  
Public And Private ◽  
The Public ◽  
Alternative Approach ◽  
Starting Point ◽  
Significant Enrichment ◽  
Traditional Societies ◽  
Definition Of

Discussion of the definition of corruption has progressed little since Heidenheimer's groundbreaking distinction between definitions centred on public opinion, public office and public interest. All these definitions have been severely criticised. I suggest that underneath these traditional concepts of corruption lurks a much older one based on distributive justice – namely the ‘impartiality principle’, whereby a state ought to treat equally those who deserve equally. This principle provides a much more plausible reason for why the public condemns corruption than alternative approaches, and, moreover, it is recognised fairly universally: the implicit distinction between ‘public’ and ‘private’ is certainly neither as ‘modern’ nor as ‘Western’ as many have claimed. The universality of the principle of impartiality does not imply universality of its content: who deserves equally, or, alternatively, on which grounds discrimination is ruled out, will be answered differently at different periods in time and will vary from society to society. The impartiality principle provides a starting point for the discussion of both corruption in ‘traditional’ societies and contemporary political corruption – corruption involving violations of specific non-discrimination norms governing the access to the political process and the allocation of rights and resources. The impartiality principle calls for rule-bound administration and thus underpins the public office definition of corruption. A central element of the analysis of corruption is the study of specific non-discrimination norms and their comparison across time and place. This approach leads to a significant enrichment of the concept of corruption.

Country Attractiveness for Offshoring and Offshore Outsourcing: Additional Considerations

2008 ◽  
Vol 23 (4) ◽  
pp. 228-231 ◽  
Author(s):  
Julia Kotlarsky ◽  
Ilan Oshri
Keyword(s):  
Information Technology ◽  
Local Knowledge ◽  
Offshore Outsourcing ◽  
Medium Term ◽  
Strategic Intent ◽  
Alternative Approach ◽  
Starting Point

In this article, we review aspects relating to the attractiveness of India for information technology offshore - outsourcing. Our starting point is that, indeed, India will remain competitive in the short-medium term. However, more importantly, we move on to argue that country attractiveness is becoming a less important issue. We consider an alternative approach to analyze country attractive in which the client's strategic intent behind going offshore and the vendor's global dispersedness and its local knowledge define the attractiveness of the firm's offshoring strategy.

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