Pseudo-Hierarchical Multistage Model for System of Systems Design and Operations

Author(s):  
Harrison M. Kim ◽  
I. Jessica Hidalgo

This paper describes a multilevel, multistage approach to system of systems design optimization where a system design is linked with system allocation along the multistage decision making horizon. The approach is composed of two parts: pseudo-hierarchical formulation (i.e., how to model the stages of multiple, separate decision making processes), and multistage coordination (i.e., how efficiently the proposed model would perform). The pseudo-hierarchical formulation integrates multilevel optimization and multistage programming to capture level-by-level and stage-by-stage system design optimization. The multistage coordination is based on the alternating directions method that is incorporated as an efficient means to solve this inherently largescale optimization problem. An example on collaborative system operation and design between an airline and an aircraft manufacturer validates the methodology where an airline plans to introduce multiple new aircraft to capture dynamically changing demand of the customers. The proposed methodology is validated against the all-in-one approach and the sequential approach.

Author(s):  
I. Jessica Hidalgo ◽  
Harrison M. Kim

Decomposition-based product design optimization under system of systems paradigm is linked with resource (i.e., product) allocation. A two-stage, system of systems approach to linking resource allocation (e.g., vehicle routing problem (VRP)) and system design optimization (e.g., vehicle design problem (VDP)) is presented. The problem inherently contains discrete variables from VRP, thus a practical formulation is presented to overcome convergence difficulty associated with shared discrete variables in a decomposed setting. Two examples, composed of four and eight air routes respectively with the introduction of a new aircraft to the existing fleet, are presented to demonstrate the effectiveness of the proposed approach. A new type of aircraft is designed and allocated to the currently existing VRP to meet the demand, while the direct operating cost of an airline is minimized.


2000 ◽  
Author(s):  
Xiaoshi Jin

Abstract Runner system design for injection molds with multiple gates or multiple cavities often requires iterative analyses for optimized results, because the gate locations or cavity shapes may not be naturally balanced. In addition, in molds with symmetrical layouts, the required injection pressure may be unnecessarily high if the runners are poorly sized. In this paper, a scheme for quickly optimizing runner system design is presented. The objective of design optimization is to minimize the required injection pressure within the design space defined by a given total runner volume. Each runner segment can be given an upper limit and lower limit to define the range of runner cross sectional dimensional size. Application examples are included to demonstrate the effectiveness of the scheme.


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