A generalized stationary point convergence theory for evolutionary algorithms (open access)

A generalized stationary point convergence theory for evolutionary algorithms

This paper presents a convergence theory for evolutionary pattern search algorithms (EPSAs). EPSAs are self-adapting evolutionary algorithms that modify the step size of the mutation operator in response to the success of previous optimization steps. Previously, the authors have proven a stationary point convergence theory for EPSAs for which the step size is not allowed to increase. The present analysis generalizes this analysis to prove a convergence theory for EPSAs that are allowed to both increase and decrease the step size. This convergence theory is based on an extension of the convergence theory for generalized pattern search methods.
Date: February 1, 1997
Creator: Hart, W.E.
Object Type: Article
System: The UNT Digital Library
Parallel auxiliary space AMG for definite Maxwell problems (open access)

Parallel auxiliary space AMG for definite Maxwell problems

Motivated by the needs of large multi-physics simulation codes, we are interested in algebraic solvers for the linear systems arising in time-domain electromagnetic simulations. Our focus is on finite element discretization, and we are developing scalable parallel preconditioners which employ only fine-grid information, similar to algebraic multigrid (AMG) for diffusion problems. In the last few years, the search for efficient algebraic preconditioners for H(curl) bilinear forms has intensified. The attempts to directly construct AMG methods had some success, see [12, 1, 7]. Exploiting available multilevel methods on auxiliary mesh for the same bilinear form led to efficient auxiliary mesh preconditioners to unstructured problems as shown in [4, 8]. A computationally more attractive approach was recently proposed by Hiptmair and Xu [5]. In contrast to the auxiliary mesh idea, the method in [5] uses a nodal H{sup 1}-conforming auxiliary space on the same mesh. This significantly simplifies the computation of the corresponding interpolation operator. In the present talk, we consider several options for constructing unstructured mesh AMG preconditioners for H(curl) problems and report a summary of computational results from [10, 9]. Our approach is slightly different than the one from [5], since we apply AMG directly to variationally constructed coarse-grid operators, …
Date: February 16, 2007
Creator: Kolev, T V & Vassilevski, P S
Object Type: Article
System: The UNT Digital Library
Preparation of northern mid-continent petroleum atlas. Quarterly report, October 1, 1996--December 31, 1996 (open access)

Preparation of northern mid-continent petroleum atlas. Quarterly report, October 1, 1996--December 31, 1996

As proposed, the second year program will continue and expand upon the Kansas elements of the original program, and provide improved on-line access to the prototype atlas. The second year of the program will result in a prototype digital atlas sufficient to demonstrate the approach and to provide a permanent improvement in data access to Kansas operators. The ultimate goal of providing an interactive history-matching interface with a regional data base remains for future development as the program covers more geographic territory and the data base expands. As part of the first year project ``Pages`` and data schema for the atlas overview and field studies were developed and made accessible through the world-wide-web. The atlas structure includes access to geologic, geophysical and production information at levels from the natural, to the regional, to the field to the individual well. Several approaches have been developed that provide efficient and flexible screening and search procedures. The prototype of the digital atlas is accessible through the Kansas Geological Survey Petroleum Research Section (PRS) HomePage (the Universal Resource locator [URL] is http://www.kgs.ukans. edu/PRS/PRS.html). The Digital Petroleum Atlas (DPA) HomePage is available directly at http://www.kgs.ukans.edu/DPA/dpaHome.html.
Date: February 4, 1997
Creator: Gerhard, Lee C.; Carr, Timothy R. & Watney, W. Lynn
Object Type: Report
System: The UNT Digital Library
Application of Diagnostic/Prognostic Methods to Critical Equipment for the Spent Nuclear Fuel Cleanup Program (open access)

Application of Diagnostic/Prognostic Methods to Critical Equipment for the Spent Nuclear Fuel Cleanup Program

The management of the Spent Nuclear Fuel (SNF) project at the Hanford K-Basin in the 100 N Area has successfully restructured the preventive maintenance, spare parts inventory requirements, and the operator rounds data requirements. In this investigation, they continue to examine the different facets of the operations and maintenance (O&M) of the K-Basin cleanup project in search of additional reliability and cost savings. This report focuses on the initial findings of a team of PNNL engineers engaged to identify potential opportunities for reducing the cost of O&M through the application of advanced diagnostics (fault determination) and prognostics (residual life/reliability determination). The objective is to introduce predictive technologies to eliminate or reduce high impact equipment failures. The PNNL team in conjunction with the SNF engineers found the following major opportunities for cost reduction and/or enhancing reliability: (1) Provide data routing and automated analysis from existing detection systems to a display center that will engage the operations and engineering team. This display will be operator intuitive with system alarms and integrated diagnostic capability. (2) Change operating methods to reduce major transients induced in critical equipment. This would reduce stress levels on critical equipment. (3) Install a limited sensor set on failure prone …
Date: February 28, 2002
Creator: Casazza, Lawrence O.; Jarrell, Donald B.; Koehler, Theresa M.; Meador, Richard J. & Wallace, Dale E.
Object Type: Report
System: The UNT Digital Library

[Photograph 2012.201.OVZ001.4701]

Photograph used for a story in the Daily Oklahoman newspaper. Caption: "Platoons of police officers hunted the rough canyons southwest of here for two bank robbers Tuesday but they found only one good clue - a hideout shack. The two men who robbed Gracemont's First National Bank and shot the president were believed to be in the vicinity of Dead Man's and Horse Thief Canyons about 2 1/2 miles southwest of here. Crime bureau agents said tracks found in and around the shack matched those found near the bandits' abandoned get-away car. They said they believed the car had been hidden in the shack Monday for use in the robbery Tuesday......One state officer believe the bandits deliberately wrecked their car on a dirt road overlooking Dead Man's Canyon in order to throw officers of the track. A second theory, the one most generally accepted by police and most of the townspeople of Gracemont is that the robbers are still in hiding. And if they are, some believe chilly weather conditions will make it almost certain the bandits will have to come out of hiding and take refuge in one of the farm homes nearby, or perhaps steal a car in …
Date: February 2, 1960
Creator: King, Cliff
Object Type: Photograph
System: The Gateway to Oklahoma History