Sequential optimization and reliability assessment for multidisciplinary systems design

Motivated by the need of high reliability and safety in complex engineering systems, recently reliability-based design has been increasingly applied in multidisciplinary design optimization (MDO). However, a direct integration of reliability-based design that has been successful in many single disciplinary fields into MDO may present tremendous implementation and numerical difficulties. The reliability analysis and reliability based designs are highly expensive for MDO considering various disciplines that are dependent on each other or coupled. Hence, the present work proposes a methodology of Sequential Optimization and Reliability Assessment for multidisciplinary systems design, to improve the efficiency of reliability-based MDO. The central idea is to decouple the reliability analysis from MDO with sequential cycles of reliability analysis and deterministic MDO and hence to reduce the computational demand --Abstract, page iii

Signaling RSVP-TE Tunnels on a Shared MPLS Forwarding Plane

The scale of MPLS RSVP-TE networks has grown, so the number of Label Switched Paths (LSPs) supported by individual network elements has increased. Various implementation recommendations have been proposed to manage the resulting increase in control plane state. However, those changes have had no effect on the number of labels that a transit Label Switching Router (LSR) has to support in the forwarding plane. That number is governed by the number of LSPs transiting or terminated at the LSR and is directly related to the total LSP state in the control plane. This document defines a mechanism to prevent the maximum size of the label space limit on an LSR from being a constraint to control plane scaling on that node. It introduces the notion of pre-installed 'per Traffic Engineering (TE) link labels' that can be shared by MPLS RSVP-TE LSPs that traverse these TE links. This approach significantly reduces the forwarding plane state required to support a large number of LSPs. This couples the feature benefits of the RSVP-TE control plane with the simplicity of the Segment Routing MPLS forwarding plane

Sequential Optimization and Reliability Assessment for Multidisciplinary Systems Design

With higher reliability and safety requirements, reliability-based design has been increasingly applied in multidisciplinary design optimization (MDO). A direct integration of reliability-based design and MDO may present tremendous implementation and numerical difficulties. In this work, a methodology of sequential optimization and reliability assessment for MDO is proposed to improve the efficiency of reliability-based MDO. The central idea is to decouple the reliability analysis from MDO with sequential cycles of reliability analysis and deterministic MDO. The reliability analysis is based on the first-order reliability method (FORM). In the proposed method, the reliability analysis and the deterministic MDO use two MDO strategies, the multidisciplinary feasible approach and the individual disciplinary feasible approach. The effectiveness of the proposed method is illustrated with two example problems