InAs quantum dots (QD) are modulated with a surface acoustic wave inducing phonon sidebands of the fluorescence. This constitutes an important step towards sideband cooling of a nanomechanical resonator via coupling to an embedded QD [1].

In this paper, we invoke probability constrained optimization to establish a framework for allocating means and tolerances in design for quality that focuses on customer satisfaction at predictable cost levels. The optimal allocation minimizes the production costs while ensuring that responses conform probabilistically to their specification limits. An overall system probability of conformance is obtained from a quality policy (e.g. defect rate, process capability index). Probabilities are evaluated using limit-state functions and fast integration methods. The three quality metrics (i.e. target/larger/smaller-is-best) and robustness are addressed naturally. The methodology is developed in detail and compared with the traditional minimum total cost approach. Optimal means and tolerances are found for an electromechanical servo system and a power division circuit to illustrate the practicality and potential of the approach. Copyright (C) 2005 John Wiley & Sons, Ltd.

Click to increase image sizeClick to decrease image sizeKeywords: Linear graph theoryReliabilityQualityConformanceFunctional topologies ACKNOWLEDGMENTS The authors take this opportunity to thank Tricia Cooper, Dorothy Kucar, and David Swan—former students in Systems Design Engineering at the University of Waterloo—for their valuable discussions on the article and the Natural Sciences and Engineering Research Council (NSERC) for their financial support during the project.

Ionized radiators and charged perturbers in a hot, dense plasma undergo cyclotron motion and experience the motional Stark effect in the presence of an external magnetic field. In this paper, we consider a magnetized two-body radiating system and indicate how the lineshape can be modified by an intense magnetic field (e.g. non-uniform magnetic fields, Doppler-Stark coupling, etc.) We then focus specifically on quasistatic properties and present results based on simulations, using one-component ion-quasiparticle molecular dynamics, of a hot dense plasma in an external magnetic field. Results are presented for the three generalized microfields p(ϵ), PB(ϵ), and ℘(ϵ) which are the B = 0 microfield, the microfield including ion cyclotron motion, and the total microfield, including the motional Stark field, respectively. We have considered short-pulse laser experiments, white dwarf atmospheres, and gas bag experiments.

There has been a great deal of interest in quality and reliability in recent years. Researchers have defined these 'system' measures specifically for use within their discipline. However, some of these definitions are incompatible when applied to other areas. The purpose of this paper is to define quality and reliability for use in all disciplines. By using a discipline-independent method to define these measures, a working definition of quality and reliability can be found. Linear graph models will help establish the definition and relationship.

This paper provides a recipe for reliability-based design of steady-state systems to provide a minimum cost design subject to the constraints on the probability of designated failure events. The method is efficient and allows for arbitrary probability distributions. The method integrates graph-theoretic models and symbolic programming for model building with structural mechanics reliability methods for quickly approximating probabilities. The resulting models can be passed to any appropriate optimization routine. In this paper, the method is described along with a supporting example

The reliability of engineering systems is usually improved by the inclusion of redundant components in the design. Often, the redundant components must all contribute actively to the operation of the system. Examples include structures, water and power distribution systems, and communication networks. For these systems, the failure of each successive component defines a different topological configuration for the system. A reliable system should perform adequately in as many of these configurations as possible. Consequently, the reliability of a system with active redundancy depends on two factors: the probability, considering component failures, that a functional system topology is maintained; and the probability of adequate system performance in each functional configuration. To date, no single reliability measure exists which combines both of these factors, but such a measure would be useful for comparison of alternative redundant designs. Current methods for reliability assessment have been tailored to the purposes of individual engineering disciplines and reflect the inherent physical properties of specific types of systems. However, an increasing need for reliability analysis of large, complex, multidisciplinary systems requires a more general and unified approach. In this paper, we propose a unified, model-based methodology for reliability-based design which provides a single, second moment reliability index for systems with active redundancy. The reliability index of a redundant pipe network is calculated as an illustrative example.