Decomposition-Based Assembly Synthesis for Structural Modularity

2004 ◽  
Vol 126 (2) ◽  
pp. 234-243 ◽  
Author(s):  
O. L. Cetin ◽  
K. Saitou
Keyword(s):  
Modular Design ◽  
Structural Strength ◽  
Local Geometry ◽  
Multi Objective Optimization ◽  
Weld Joints ◽  
Trade Offs ◽  
Optimization Formulation ◽  
Definition Of ◽  
Manufacturability Evaluation

A method for modular design of structural products such as automotive bodies is presented where two structural products are simultaneously decomposed to components considering the structural performances of each structure and the component sharing between two structures. The problem is posed as an optimization to minimize the reduction of structural strength due to the introduction of spot-weld joints and the number of redundant joints, while maximizing the manufacturability of the component and component sharing between two structures. As an extension to our previous work, this paper focuses on the simultaneous decomposition of two 3D beam-based structures. The major extensions include 1) a new, realistic definition of feasible joining angles based on the local geometry of joining components, 2) a component manufacturability evaluation that eliminates the need of specifying the number of components prior to decomposition and 3) a multi-objective optimization formulation that allows an effective exploration of trade-offs among different criteria. A case study on the simplified, 3D beam models of automotive bodies is presented to demonstrate the developed method.

scholarly journals Rapid design of aircraft fuel quantity indication systems via multi-objective evolutionary algorithms

2020 ◽  
pp. 1-18
Author(s):  
David Judt ◽  
Craig Lawson ◽  
Albert S.J. van Heerden
Keyword(s):  
System Level ◽  
Fluid Systems ◽  
Trade Offs ◽  
Aircraft Fuel ◽  
Definition Of ◽  
Tank Geometry ◽  
Probe Set ◽  
Accuracy Constraints ◽  
Good Agreement

The design of electrical, mechanical and fluid systems on aircraft is becoming increasingly integrated with the aircraft structure definition process. An example is the aircraft fuel quantity indication (FQI) system, of which the design is strongly dependent on the tank geometry definition. Flexible FQI design methods are therefore desirable to swiftly assess system-level impact due to aircraft level changes. For this purpose, a genetic algorithm with a two-stage fitness assignment and FQI specific crossover procedure is proposed (FQI-GA). It can handle multiple measurement accuracy constraints, is coupled to a parametric definition of the wing tank geometry and is tested with two performance objectives. A range of crossover procedures of comparable node placement problems were tested for FQI-GA. Results show that the combinatorial nature of the probe architecture and accuracy constraints require a probe set selection mechanism before any crossover process. A case study, using approximated Airbus A320 requirements and tank geometry, is conducted and shows good agreement with the probe position results obtained with the FQI-GA. For the objectives of accessibility and probe mass, the Pareto front is linear, with little variation in mass. The case study confirms that the FQI-GA method can incorporate complex requirements and that designers can employ it to swiftly investigate FQI probe layouts and trade-offs.

Decomposition-Based Assembly Synthesis of Multiple Structures for Minimum Manufacturing Cost

2004 ◽  
Vol 127 (4) ◽  
pp. 572-579 ◽  
Author(s):  
Onur L. Cetin ◽  
Kazuhiro Saitou
Keyword(s):  
Genetic Algorithm ◽  
Early Identification ◽  
Economies Of Scale ◽  
Structural Strength ◽  
Manufacturing Cost ◽  
Manufacturing Costs ◽  
Multiobjective Genetic Algorithm ◽  
Trade Offs ◽  
Multiple Structures

An extension of decomposition-based assembly synthesis for structural modularity is presented where the early identification of shareable components within multiple structures is posed as an outcome of the minimization of estimated manufacturing costs. The manufacturing costs of components are estimated under given production volumes considering the economies of scale. Multiple structures are simultaneously decomposed, and the types of welded joints at component interfaces are selected from a given library, in order to minimize the overall manufacturing cost and the reduction of structural strength due to the introduction of joints. A multiobjective genetic algorithm is used to allow effective examination of trade-offs between manufacturing cost and structural strength. A new joint-oriented representation of structures combined with a “direct” crossover is introduced to enhance the efficiency of the search. A preliminary case study with two simplified aluminum space frame automotive bodies is presented to demonstrate that not all types of component sharing are economically justifiable under a certain production scenario.

scholarly journals Decomposition-Based Assembly Synthesis of Multiple Structures for Minimum Production Cost

2003 ◽  
Author(s):  
Onur L. Cetin ◽  
Kazuhiro Saitou
Keyword(s):  
Production Cost ◽  
Economies Of Scale ◽  
Structural Strength ◽  
Production Costs ◽  
Manufacturing Cost ◽  
Manufacturing Costs ◽  
Multiobjective Genetic Algorithm ◽  
Trade Offs ◽  
Multiple Structures

An extension of decomposition-based assembly synthesis for structural modularity is presented where the early identification of shareable components within multiple structures is posed as an outcome of the minimization of estimated production costs. The manufacturing costs of components are estimated under given production volumes considering the economies of scale. Multiple structures are simultaneously decomposed and the types of welded joints at component interfaces are selected from a given library, in order to minimize the overall production cost and the reduction of structural strength due to the introduction of joints. A multiobjective genetic algorithm is utilized to allow effective examination of trade-offs between manufacturing cost and structural strength. A new joint-oriented representation of structures combined with a “direct” crossover is introduced to enhance the efficiency of the search. A case study with two aluminum space frame automotive bodies is presented to demonstrate that not all types of component sharing are economically justifiable under a certain production scenario.

Empowering Women Entrepreneurs Through Microfinance - A Case of Rural Bangladesh

2017 ◽  
Vol 3 (2) ◽  
pp. 7
Author(s):  
Saida Parvin
Keyword(s):  
Women's Empowerment ◽  
Assessment Tools ◽  
Women’S Empowerment ◽  
Case Study Method ◽  
Policy Makers ◽  
Theoretical Contribution ◽  
Donor Agencies ◽  
Definition Of ◽  
The Impact

Women’s empowerment has been at the centre of research focus for many decades. Extant literature examined the process, outcome and various challenges. Some claimed substantial success, while others contradicted with evidence of failure. But the success remains a matter of debate due to lack of empirical evidence of actual empowerment of women around the world. The current study aimed to address this gap by taking a case study method. The study critically evaluates 20 cases carefully sampled to include representatives from the entire country of Bangladesh. The study demonstrates popular beliefs about microfinance often misguide even the borrowers and they start living in a fabricated feeling of empowerment, facing real challenges to achieve true empowerment in their lives. The impact of this finding is twofold; firstly there is a theoretical contribution, where the definition of women’s empowerment is proposed to be revisited considering findings from these cases. And lastly, the policy makers at governmental and non-governmental organisations, and multinational donor agencies need to revise their assessment tools for funding.

The Rapid Iterative Test and Evaluation Method (RITE)

2018 ◽  
Author(s):  
Michael C. Medlock
Keyword(s):  
Evaluation Method ◽  
Test And Evaluation ◽  
Original Case ◽  
Definition Of

This chapter begins with a discussion of the philosophy and then definition of the RITE method. It then delves into the benefits of this method and provides practical notes on running RITE tests effectively. The chapter concludes with an overview of the original case study behind the 2002 article documenting this method.

Decision Processes and Value Endogeneity

2018 ◽  
Author(s):  
James G. March
Keyword(s):  
Decision Processes ◽  
Hard Problem ◽  
Trade Offs ◽  
Definition Of ◽  
Over Time ◽  
What Matters

Humans use reasons to shape and justify choices. In the process, trade-offs seem essential and often inevitable. But trade-offs involve comparisons, which are problematic both across values and especially over time. Reducing disparate values to a common metric (especially if that metric is money) is often problematic and unsatisfactory. Critically, it is not that values just shape choices, but that choices themselves shape values. This endogeneity of values makes an unconditional normative endorsement of modern decision-theoretic rationality unwise. This is a hard problem and there is no escaping the definition of good values, that is, those that make humans better. This removes the wall between economics and philosophy. If we are to adopt and enact this perspective, then greater discourse and debate on what matters and not just what counts will be useful and even indispensable.

Poe and His Global Advocates

2018 ◽  
pp. 596-617
Author(s):  
Emron Esplin
Keyword(s):  
Twentieth Century ◽  
South America ◽  
Rio De La Plata ◽  
Río De La Plata ◽  
Literary Traditions ◽  
La Plata ◽  
Original Works ◽  
Definition Of ◽  
Global Reputation

This essay explores Edgar Allan Poe’s extraordinary relationships with various literary traditions across the globe, posits that Poe is the most influential US writer on the global literary scene, and argues that Poe’s current global reputation relies at least as much on the radiance of the work of Poe’s literary advocates—many of whom are literary stars in their own right—as it does on the brilliance of Poe’s original works. The article briefly examines Poe’s most famous French advocates (Baudelaire, Mallarmé, Valéry); glosses the work of his advocates throughout Europe, Asia, and the Americas; and offers a concise case study of Poe’s influence on and advocacy from three twentieth-century writers from the Río de la Plata region of South America (Quiroga, Borges, and Cortázar). The essay concludes by reading the relationships between Poe and his advocates through the ancient definition of astral or stellar influence.

scholarly journals Looking for Answers to Food Loss and Waste Management in Spain from a Holistic Nutritional and Economic Approach

2020 ◽  
Vol 13 (1) ◽  
pp. 125
Author(s):  
Jara Laso ◽  
Cristina Campos ◽  
Ana Fernández-Ríos ◽  
Daniel Hoehn ◽  
Andrea del Río ◽  
...  
Keyword(s):  
Agricultural Production ◽  
Decision Making Process ◽  
Economic Approach ◽  
Multi Objective Optimization ◽  
Food Supply Chain ◽  
Food Loss ◽  
Reduction Strategies ◽  
Definition Of ◽  
New Strategies ◽  
Specific Food

The generation of food loss and waste (FLW) is a global problem for worldwide politics. About one-third of the food produced ends up in the rubbish before it is consumed. For this reason, it is essential to design and implement new strategies along the food supply chain (FSC) with the aim of reducing this FLW at each stage. However, not only mass quantification should be considered, but also economic and nutritional performance. The novelty of this study is the definition of a methodology based on the “distance to target” approach by means of multi-objective optimization to evaluate the economic and nutritional cost produced by this FLW. This methodology was applied to the Spanish food basket in 2015. The results revealed that 80% of the total FLW generated in economic and nutritional terms is concentrated in the agricultural production (53.3%) and consumption (26.3%) stages. In the first stages of the FSC, fruits (Dn eq.= 0.7), cereals (Dn eq.= 0.61), and vegetables (Dn eq.= 0.57) were the furthest from the distance target due to the great amount of FLW generated. Moreover, according to the normalized weighted distances obtained from the minimization of economic and nutritional cost, pulses (Dn eq. = 0.05–0.03) and eggs (Dn eq. = 0.02) were the more efficient food categories. The methodology described in this study proposes a single index to quantify the economic and nutritional cost of different food categories to facilitate the decision-making process. This index makes possible the definition of reduction strategies focused on specific food categories and depending on the FSC stage.

scholarly journals Sustainability and Stakeholder Awareness: A Case Study of a Scottish University

2021 ◽  
Vol 13 (8) ◽  
pp. 4186
Author(s):  
Abdulhakeem Raji ◽  
Abeer Hassan
Keyword(s):  
Signaling Theory ◽  
Relevant Information ◽  
Voluntary Exercise ◽  
Communication Tool ◽  
Individual Interviews ◽  
Study Approach ◽  
Research Findings ◽  
Definition Of ◽  
The University

This paper adopted a case study approach to investigate the sustainability practices of a Scottish university in order to understand if sustainability forms part of its central policy agenda. As such, the paper focuses on the levels of awareness and disclosure of their sustainable practices, measuring the impacts and effectiveness of those initiatives. This paper introduces signaling theory to explore the idea that appropriate communication via integrated thinking can close the gap between the organization and its stakeholders. We believe that the provision of this relevant information will lead to better communication between the organization and its stakeholders, supporting a signaling theory interpretation. Therefore, we are suggesting that integrated thinking is an internal process that organizations can follow to increase the level of disclosure as a communication tool with stakeholders. From the literature reviewed, four themes were identified (definition of university sustainability, sustainability awareness, disclosure framework within universities, and level of accountability). The research adopted a pragmatic view and conducted individual interviews with participants belonging to three stakeholder groups (members of the university’s senior management, the governing council, and the student union executive). Although this study focused on just one Scottish university, it should still provide some insight for the better understanding of the underpinning issues surrounding the sustainability accountability practices of Scottish universities in general. The research findings indicated that the university prioritized only two sustainability dimensions—economic and environmental—and that the university still perceived sustainability as a voluntary exercise. Additionally, it is evident that the university had no framework in place for measuring its sustainability delivery—and therefore had no established medium of communicating these activities to its stakeholders. Moreover, research findings showed that the social and educational context of sustainability was lacking at the university. The university has done little or nothing to educate its stakeholders on sustainability.

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