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 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.

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.

Evaluating The Effectiveness Of Problem-Based Learning (Pbl) Implemented In The Textile Engineering Course - A Case Study On Ahsanullah University Of Science And Technology, Bangladesh

2014 ◽  
Vol 1 (1) ◽  
pp. 111-114
Author(s):  
Lal Mohan Baral ◽  
Ramzan Muhammad ◽  
Claudiu Vasile Kifor ◽  
Ioan Bondrea
Keyword(s):  
Engineering Students ◽  
Science And Technology ◽  
Problem Based Learning ◽  
Professional Life ◽  
System Level ◽  
Teaching Tool ◽  
Technical Problems ◽  
Empirical Survey ◽  
Undergraduate Programs

AbstractProblem-based learning as a teaching tool is now used globally in many areas of higher education. It provides an opportunity for students to explore technical problems from a system-level perspective and to be self-directed life-long learner which is mandatory for equipping engineering students with the skill and knowledge. This paper presents a case study illustrating the effectiveness of implemented Problem-based learning (PBL) during five semesters in the undergraduate programs of Textile Engineering in Ahsanullah University of Science and Technology (AUST). An assessment has been done on the basis of feedback from the students as well as their employers by conducting an empirical survey for the evaluation of PBL impact to enhance the student's competencies. The Evaluations indicate that students have achieved remarkable competencies through PBL practices which helped them to be competent in their professional life.

A Methodology for Characterizing System-Level ESD Sensitivity

2004 ◽  
Author(s):  
Marie-Pascale Chagny ◽  
John A. Naoum
Keyword(s):  
Electrostatic Discharge ◽  
Computer Systems ◽  
Electronic Equipment ◽  
Experimental Methodology ◽  
Computer Users ◽  
System Level ◽  
Permanent Damage ◽  
Design Improvement ◽  
Desktop Computers

Abstract Over the years, failures induced by an electrostatic discharge (ESD) have become a major concern for semiconductor manufacturers and electronic equipment makers. The ESD events that cause destructive failures have been studied extensively [1, 2]. However, not all ESD events cause permanent damage. Some events lead to recoverable failures that disrupt system functionality only temporarily (e.g. reboot, lockup, and loss of data). These recoverable failures are not as well understood as the ones causing permanent damage and tend to be ignored in the ESD literature [3, 4]. This paper analyzes and characterizes how these recoverable failures affect computer systems. An experimental methodology is developed to characterize the sensitivity of motherboards to ESD by simulating the systemlevel ESD events induced by computer users. The manuscript presents a case study where this methodology was used to evaluate the robustness of desktop computers to ESD. The method helped isolate several weak nets contributing to the failures and identified a design improvement. The result was that the robustness of the systems improved by a factor of 2.

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.

Minority Presidents in a Coalitional World

2018 ◽  
Author(s):  
Paul Chaisty ◽  
Nic Cheeseman ◽  
Timothy J. Power
Keyword(s):  
Coalition Formation ◽  
Cost Minimization ◽  
Analytical Framework ◽  
System Level ◽  
Current State ◽  
Key Concepts ◽  
Definition Of

This chapter summarizes the main parameters of coalitional presidentialism and the key concepts, definitions, explanatory frameworks, indicators, and propositions. It summarizes our understanding of coalitional presidentialism; the distinction between coalition formation and maintenance; the definition of coalitions; the multidimensional understanding of coalition management (the ‘presidential toolbox’); and an analytical framework that emphasizes the motivation of presidents to achieve cost minimization under constraints determined by system-level, coalition-level, and conjunctural factors. It also summarizes our main empirical findings: (1) the characteristics of presidential tools, (2) the substantive patterns of their deployment, (3) the factors that shape the costs of using these tools, (4) the actual (observed) costs of using them, and (5) the potential for imperfect substitutability of these tools. Finally, it concludes with some reflections on the current state of the research on comparative presidentialism.

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.

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