Systems Engineering Commons^™

Efficiently Estimating Survival Signature And Two-Terminal Reliability Of Heterogeneous Networks Through Multi-Objective Optimization, Daniel Bruno Lopes Da Silva

Graduate Theses and Dissertations

The two-terminal reliability problem is a classical reliability problem with applications in wired and wireless communication networks, electronic circuit design, computer networks, and electrical power distribution, among other systems. However, the two-terminal reliability problem is among the hardest combinatorial problems and is intractable for large, complex networks. Several exact methods to solve the two-terminal reliability problem have been proposed since the 1960s, but they have exponential time complexity in general. Hence, practical studies involving large network-type systems resort to approximation methods to estimate the system's reliability. One attractive approach for quantifying the reliability of complex systems is to use signatures, …

Reliability And Cost Impacts For Attritable Systems, Bryan R. Bentz

Theses and Dissertations

Attritable systems trade system attributes like reliability and reparability to achieve lower acquisition cost and decrease cost risk. Ultimately, it is hoped that by trading these attributes the amount of systems able to be acquired will be increased. However, the effect of trading these attributes on system-level reliability and cost risk is difficult to express complicated reparable systems like an air vehicle. Failure-time and cost data from a baseline limited-life air vehicle is analyzed for this reliability and reparability trade study. The appropriateness of various reliability and cost estimation techniques are examined for these data. This research employs the cumulative …

Essays On Optimization And Modeling Methods For Reliability And Reliability Growth, Thomas Paul Talafuse

Graduate Theses and Dissertations

This research proposes novel solution techniques in the realm of reliability and reliability growth. We first consider a redundancy allocation problem to design a system that maximizes the reliability of a complex series-parallel system comprised of components with deterministic reliability. We propose a new meta-heuristic, inspired by the behavior of bats hunting prey, to find component allocation and redundancy levels that provide optimal or near-optimal system reliability levels. Each component alternative has an associated cost and weight and the system is constrained by cost and weight factors. We allow for component mixing within a subsystem, with a pre-defined maximum level …

Standardizing Functional Safety Assessments For Off-The-Shelf Instrumentation And Controls, Andrew Michael Nack

Masters Theses

It is typical for digital instrumentation and controls, used to manage significant risk, to undergo substantial amounts of scrutiny. The equipment must be proven to have the necessary level of design integrity. The details of the scrutiny vary based on the particular industry, but the ultimate goal is to provide sufficient evidence that the equipment will operate successfully when performing their required functions.

To be able to stand up to the scrutiny and more importantly, successfully perform the required safety functions, the equipment must be designed to defend against random hardware failures and also to prevent systematic faults. These design …

Cloud Computing, Contractibility, And Network Architecture, Christopher S. Yoo

All Faculty Scholarship

The emergence of the cloud is heightening the demands on the network in terms of bandwidth, ubiquity, reliability, latency, and route control. Unfortunately, the current architecture was not designed to offer full support for all of these services or to permit money to flow through it. Instead of modifying or adding specific services, the architecture could redesigned to make Internet services contractible by making the relevant information associated with these services both observable and verifiable. Indeed, several on-going research programs are exploring such strategies, including the NSF’s NEBULA, eXpressive Internet Architecture (XIA), ChoiceNet, and the IEEE’s Intercloud projects.

Determining A Reliability Factor For Photovoltaic's In San Luis Obispo, Ryan S. Roach

Industrial and Manufacturing Engineering

This project will analyze raw photovoltaic (PV) solar panel performance data in order to determine a reliability factor for solar panels in San Luis Obispo. This project is a subset of a larger project being performed by SLO RESCO, which is funded by a grant from the California Energy Commission. Their project will explore the use of solar, wind, geothermal, and biomass renewable resources. The scope of this project is limited to a small section of RESCO's analysis of solar panel technology and implementation in which a reliability factor will be generated.

The objective is to determine a reliability factor …

The Optimization Of The Threshold For The Preventive Maintenance Actions In A Condition-Based Maintenance Program Via Dynamic Programming Approach, Kamran Shahanaghi, Mehdi Jafarian, Majid Beikverdi, Zeinab Nezhadbiglari

Mehdi Jafarian

The last step of a condition based maintenance (CBM) program is maintenance decision-making. This step is the most important and the most critical stage of maintenance for executive personnel and management whom work on taking maintenance actions. This decision making would be done according to certain criteria such as risk, cost, reliability and availability. This paper considered a dynamic programming model to optimization of the threshold for the preventive maintenance actions in a condition-based maintenance program. The basis of this modeling is the average cost of maintenance actions, failures and exchanges. In this paper, we improved the memory of the …

The Optimization Of The Threshold For The Preventive Maintenance Actions In A Condition-Based Maintenance Program Via Dynamic Programming Approach, Mehdi Jafarian, Majid Beikverdi, Kamran Shahanaghi, Zeinab Nezhadbiglari

Mehdi Jafarian

The last step of a condition based maintenance (CBM) program is maintenance decision-making. This step is the most important and the most critical stage of maintenance for executive personnel and management whom work on taking maintenance actions. This decision making would be done according to certain criteria such as risk, cost, reliability and availability. This paper considered a dynamic programming model to optimization of the threshold for the preventive maintenance actions in a condition-based maintenance program. The basis of this modeling is the average cost of maintenance actions, failures and exchanges. In this paper, we improved the memory of the …

Reliability Trend Analyses With Statistical Confidence Limits Using The Luke Reliability Trend Chart, Stephen R. Luke

Engineering Management & Systems Engineering Theses & Dissertations

In electronic systems, it is interesting to understand exactly how the reliability is changing with time. Dynamic performance changes when a system passes from infant mortality stage into useful life phase and when the system passes from useful life phase into wearout phase. Dynamic performance also changes when the system is redesigned or when the system is acted on by a number of other outside forces such as a change in maintenance policy, escalation of alignment problems, or a change in training program. It is important to know when a system is changing dynamically in order to assess design, policy …