Extreme Design Events due to Combined, Non-Gaussian Loading

A major design driver for marine systems is lifetime performance. How a vessel responds in harsh environments has stark consequences for safety and operability, necessitating the consideration of lifetime performance analysis during the design stage. However, extreme events associated with marine dynamic systems may not be caused by the most extreme ocean environments, like the largest wave. Some severe vessel responses may be due to simultaneous combinations of potentially correlated, non-Gaussian loading, which may be excited by any number of wave profiles. Different analytical methods based on extrapolation or solving for threshold exceedances can examine certain aspects of this problem: extreme system responses, combined loading, and long exposures to harsh excitation. But these methods, in general, do not retain the wave profiles which lead to extreme responses. These waves profiles can drive high-fidelity codes, like Computational Fluid Dynamics or Finite Element Analysis time-domain simulations, to give pressure and loading distributions. Such analyses can give an overall account of a system during lifetime events and refine estimates of system performance due to lifetime loading. The Design Loads Generator (DLG) was developed to construct wave profiles that lead to a distribution of linear extreme responses, given an operational profile and exposure period. However, there are some limitations when applying the DLG method to non-linear problems. Some marine systems may experience extreme responses due to varying combinations of non-linear loading. If those loads are strongly correlated, or have an unknown correlation, it is unclear how the capability of the DLG, which considers a single linear load, can be utilized. It may also be desirable to consider lifetime system performance, and not performance conditioned on a specific excitation input, as is estimated by the DLG framework. This dissertation addresses those concerns by expanding the DLG method to what is called the non-linear Design Loads Generator (NL-DLG) process. Given a complex system, operational profile, and exposure, the NL-DLG process uses the DLG capability to determine an ensemble of excitation inputs which lead to lifetime extreme events. Unlike the DLG, which is developed for a single response, the NL-DLG process considers the interaction of multiple stochastic processes which excite the system. These processes, which may be non-Gaussian, are examined so that the resulting ensemble of excitation inputs are demonstrably exhaustive in generating possible defined responses. Short excitation inputs are constructed that estimate the same distribution of responses as would full Monte Carlo Simulations (MCS). Instead of conducting the necessary large number of full-exposure MCS for converged statistics of joint responses, the ensemble of short excitation inputs assembled by the NL-DLG process approximates that same distribution. Various examples are given in this dissertation where comparisons between MCS and NL-DLG extreme value probabilities validate the method. For a complex system with a threshold of allowable responses, the ensemble of NL-DLG generated inputs can estimate an exceedance probability, given the exposure and operational profile. This threshold may be multi-dimensional and a non-linear function of multiple loads. The NL-DLG process examines complex system responses due to combined loading, and maintains links back to the excitation environment, without the computational cost associated with brute-force MCS. These capabilities give deeper insights into system responses, and aid in the design of safer, better operating systems.PHDNaval Architecture & Marine EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/144024/1/harleigh_1.pd

Connection and Escape: Washtenaw Youth Center Library System

With the grant support, we helped overhaul the Washtenaw Youth Center libraries. We choose books that celebrate diversity to replace the old, outdated books currently in the libraries. Working with a children's librarian helped us incorporate their interests in the new book choices. The new library helps promote literacy while celebrating diversity.University Library's Student Engagement Programhttp://deepblue.lib.umich.edu/bitstream/2027.42/122854/1/Seyffert_Harleigh_FinalReport_Paper.pdfDescription of Seyffert_Harleigh_FinalReport_Paper.pdf : Final project repor

Constraining viewing geometries of pulsars with single-peaked gamma-ray profiles using a multiwavelength approach

Since the launch of the Large Area Telescope (LAT) on board the Fermi spacecraft in June 2008, the number of observed gamma-ray pulsars has increased dramatically. A large number of these are also observed at radio frequencies. Constraints on the viewing geometries of 5 of 6 gamma-ray pulsars exhibiting single-peaked gamma-ray profiles were derived using high-quality radio polarization data (Weltevrede et al., 2010). We obtain independent constraints on the viewing geometries of 6 by using a geometric emission code to model the Fermi LAT and radio light curves (LCs). We find fits for the magnetic inclination and observer angles by searching the solution space by eye. Our results are generally consistent with those previously obtained (Weltevrede et al., 2010), although we do find small differences in some cases. We will indicate how the gamma-ray and radio pulse shapes as well as their relative phase lags lead to constraints in the solution space. Values for the flux correction factor corresponding to the fits are also derived (with errors).Comment: 6 pages, 2 figures, 1 table, Proceedings of SAIP2011, the 56th Annual Conference of the South African Institute of Physics (ISBN: 978-1-86888-688-3), ed. I. Basson and A. E. Botha, http://www.saip.org.za, pp. 531-53

Analysis and Classification of British-Canadian Children's Traditional Singing Games

Ann Osborn-Seyffert raconte comment elle a essayé de développer un programme denseignement musical basé sur le système elle avait étudié en Hongrie. En se servant des collections Creighton et Fowke, aussi bien que des résultats de ses propres recherches sur le terrain, elle décrit comment analyser à laide de lordinateur les mélodies communes des chansons denfants courantes au Canada

Fan motives for interacting on social media – the example of the International Table Tennis Federation and Facebook

Social media has become an important tool for sport organisations to interact with fans. In particular for sports that have smaller marketing budgets and that do not receive mainstream media coverage on a daily basis, social media platforms provide unique communication and marketing opportunities to overcome such challenges. This study investigates the motives of fans to communicate on the Facebook page of the International Table Tennis Federation (ITTF). It is the first study that focuses on the use of social media in the context of an international sport federation. Knowledge about the gratifications sought by fans while interacting on social media is important for organisations to develop more customised online content, as this may help to reach further goals such as maintaining public interest, reinforcing brand awareness or developing closer relationships with stakeholders. We extend the academic understanding of sport fans’ motives in the context of social media and derive implications that can be relevant for managers of (niche) sport organisations with limited financial and personal resources

Controlled glass bead peening Patent

Method and apparatus for inducing compressive stresses in pressure vessel to prevent stress corrosio