scholarly journals Socio-Spatial Pareto Frontiers of Twitter Networks

Author(s):  
Brandon Oselio ◽  
Alex Kulesza ◽  
Alfred Hero
Keyword(s):  
1999 ◽  
Author(s):  
Achille Messac ◽  
Glynn Sundararaj ◽  
Ravindra Tappeta ◽  
John Renaud

2012 ◽  
Vol 591-593 ◽  
pp. 2624-2627
Author(s):  
Xu Zhong Wu ◽  
Sheng Jing Tang ◽  
Jie Guo

This paper deals with the reentry trajectory optimization problem for lunar return with consideration of entry vehicle’s fore-body shape. Three performance objectives are applied in this work: cross range, peak heat flux and total heat load. Aerothermodynamic models are based on modified Newtonian impact theory and semi-empirical correlations for convective and radiative stagnation-point heat transfer. A population based evolutionary algorithm has been executed to optimize the multidisciplinary problem. At last the numerical example showed the Pareto frontiers for spherical segment and sphere cone respectively, one of optimal trajectory designs selected from the Pareto frontiers are showed in this paper. The mission requirements are satisfied through the aerothermodynamic balance.


AIAA Journal ◽  
2014 ◽  
Vol 52 (11) ◽  
pp. 2480-2490
Author(s):  
Matthew J. Daskilewicz ◽  
Brian J. German

Author(s):  
Gary M. Stump ◽  
Mike Yukish ◽  
Timothy W. Simpson ◽  
E. Nathan Harris

We have developed a data visualization interface that facilitates a design by shopping paradigm, allowing a decision-maker to form a preference by viewing a rich set of good designs and use this preference to choose an optimal design. Design automation has allowed us to implement this paradigm, since a large number of designs can be synthesized in a short period of time. The interface allows users to visualize complex design spaces by using multi-dimensional visualization techniques that include customizable glyph plots, parallel coordinates, linked views, brushing, and histograms. As is common with data mining tools, the user can specify upper and lower bounds on the design space variables, assign variables to glyph axes and parallel coordinate plots, and dynamically brush variables. Additionally, preference shading for visualizing a user’s preference structure and algorithms for visualizing the Pareto frontier have been incorporated into the interface to help shape a decision-maker’s preference. Use of the interface is demonstrated using a satellite design example by highlighting different preference structures and resulting Pareto frontiers. The capabilities of the design by shopping interface were driven by real industrial customer needs, and the interface was demonstrated at a spacecraft design conducted by a team at Lockheed Martin, consisting of Mars spacecraft design experts.


Author(s):  
Damien Chablat ◽  
Ste´phane Caro ◽  
Raza Ur-Rehman ◽  
Philippe Wenger

This paper deals with the comparison of planar parallel manipulator architectures based on a multi-objective design optimization approach. The manipulator architectures are compared with regard to their mass in motion and their regular workspace size, i.e., the objective functions. The optimization problem is subject to constraints on the manipulator dexterity and stiffness. For a given external wrench, the displacements of the moving platform have to be smaller than given values throughout the obtained maximum regular dexterous workspace. The contributions of the paper are highlighted with the study of 3-PRR, 3-RPR and 3-RRR planar parallel manipulator architectures, which are compared by means of their Pareto frontiers obtained with a genetic algorithm.


Author(s):  
Philippe Gauthier ◽  
David Molyneux

This paper presents a cost driven, high-level optimization of Offshore Supply Vessel (OSV) operations in the Flemish Pass sector. This is an area located in the offshore waters of Newfoundland where significant oil discoveries were made in recent years, but where oil extraction will pose logistical challenges due to the increased distance from shore bases. In the first part of this paper, a simple non-linear programming model is used to minimize the monthly costs to supply a hypothetical offshore oil installation located in the Flemish Pass and to assess whether hypothetical fast supply vessels make economic sense. The second part of this paper explores the application of Pareto frontiers to the non-linear system, to evaluate the impact of schedule slack on costs, but also to look at winter operations in the Flemish Pass area.


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