Accurately measuring MPI broadcasts in a computational grid (open access)

Accurately measuring MPI broadcasts in a computational grid

An MPI library's implementation of broadcast communication can significantly affect the performance of applications built with that library. In order to choose between similar implementations or to evaluate available libraries, accurate measurements of broadcast performance are required. As we demonstrate, existing methods for measuring broadcast performance are either inaccurate or inadequate. Fortunately, we have designed an accurate method for measuring broadcast performance, even in a challenging grid environment. Measuring broadcast performance is not easy. Simply sending one broadcast after another allows them to proceed through the network concurrently, thus resulting in inaccurate per broadcast timings. Existing methods either fail to eliminate this pipelining effect or eliminate it by introducing overheads that are as difficult to measure as the performance of the broadcast itself. This problem becomes even more challenging in grid environments. Latencies a long different links can vary significantly. Thus, an algorithm's performance is difficult to predict from it's communication pattern. Even when accurate pre-diction is possible, the pattern is often unknown. Our method introduces a measurable overhead to eliminate the pipelining effect, regardless of variations in link latencies. choose between different available implementations. Also, accurate and complete measurements could guide use of a given implementation to improve application …
Date: May 6, 1999
Creator: T, Karonis N & de Supinski, B R
Object Type: Article
System: The UNT Digital Library
Ashcroft Pressure Switch Monitor for Low SCHe Purge Pressure (open access)

Ashcroft Pressure Switch Monitor for Low SCHe Purge Pressure

None
Date: May 6, 1999
Creator: Van Katwijk, Carl
Object Type: Report
System: The UNT Digital Library
Beam tests of the 12 MHz RFQ RIB injector for ATLAS. (open access)

Beam tests of the 12 MHz RFQ RIB injector for ATLAS.

Beam tests of the ANL 12 MHz Radio-Frequency Quadruple (RFQ), designed for use as the initial element of an injector system for radioactive beams into the existing ATLAS accelerators, are in progress. Recent high-voltage tests of the RFQ without beam achieved the design intervane voltage of 100 kV CW, enabling beam tests with A/q as large as 132 using beams from the ANL Physics Division 4 MV Dynamitron accelerator facility. Although the RFQ was designed for bunched beams, initial tests have been performed with unbunched beams. Experiments with stable, unbunched beams of singly-charged {sup 132}Xe and {sup 84}Kr measured the output beam energy distribution as a function of the RFQ operating voltage. The observed energies are in excellent agreement with numerical beam simulations.
Date: May 6, 1999
Creator: Clifft, B. E.; Kaye, R. A.; Kedzie, M. & Shepard, K. W.
Object Type: Article
System: The UNT Digital Library
Comparison of the corrosion behaviors of the glass-bonded sodalite ceramic waste form and reference HLW glasses. (open access)

Comparison of the corrosion behaviors of the glass-bonded sodalite ceramic waste form and reference HLW glasses.

A glass-bonded sodalite ceramic waste form is being developed for the long-term immobilization of salt wastes that are generated during spent nuclear fuel conditioning activities. A durable waste form is prepared by hot isostatic pressing (HIP) a mixture of salt-loaded zeolite powders and glass frit. A mechanistic description of the corrosion processes is being developed to support qualification of the CWF for disposal. The initial set of characterization tests included two standard tests that have been used extensively to study the corrosion behavior of high level waste (HLW) glasses: the Material Characterization Center-1 (MCC-1) Test and the Product Consistency Test (PCT). Direct comparison of the results of tests with the reference CWF and HLW glasses indicate that the corrosion behaviors of the CWF and HLW glasses are very similar.
Date: May 6, 1999
Creator: Ebert, W. L. & Lewis, M. A.
Object Type: Article
System: The UNT Digital Library
Coupling various methods for convection-diffusion problems with applications to flows in porous media (open access)

Coupling various methods for convection-diffusion problems with applications to flows in porous media

None
Date: May 6, 1999
Creator: Lazrov, R D; Pasciak, J E & Vassilevski, P S
Object Type: Article
System: The UNT Digital Library
Criticality safety evaluation - an endusers's perspective (open access)

Criticality safety evaluation - an endusers's perspective

This paper presents criticality safety evaluations from an enduser's perspective. Overall issues related to a criticality safety evaluation in an operations support setting are discussed. A work flow process is presented which shows the key steps in conducting an effective criticality evaluation. Finally, a few suggestions are given to assist newcomers to this field.
Date: May 6, 1999
Creator: Huang, S T
Object Type: Article
System: The UNT Digital Library
The effect of lattice mismatch on epitaxial La{sub 0.67}Ca{sub 0.33}MnO{sub 3} films. (open access)

The effect of lattice mismatch on epitaxial La{sub 0.67}Ca{sub 0.33}MnO{sub 3} films.

We present a study of the effect of lattice mismatch on the structure and magneto-transport properties of La{sub 0.67}Ca{sub 0.33}MnO{sub 3} (LCMO) epitaxial films. Pulsed laser deposition was used to synthesize epitaxial LCMO thin films on LaAlO{sub 3} (LAO), NdGaO{sub 3} (NGO), SrTiO{sub 3} (STO), and MgO substrates. Our results show that the nature of the lattice mismatch and the structure of the substrate governs the microstructure of the film. The microstructure consists of domains of two crystal structures, a pseudo-cubic phase and a monoclinic phase. The monoclinic phase forms as the film relaxes away from the interface, with an orientation dependent on whether the film is under a tensile or compressive in-plane strain. A special case is observed on NGO where the orthorhombic nature of the substrate results in the alignment of the monoclinic phase so that its long axis is in the plane. The observation of an in-plane anisotropy in the magnetoresistance data for LCMO on NGO suggests that the monoclinic phase is important in explaining the magneto-transport properties.
Date: May 6, 1999
Creator: Eastell, C. J.; Lin, Y.-K. & Miller, D. J.
Object Type: Article
System: The UNT Digital Library
Environmental Assessment Offsite Thermal Treatment of Low-Level Mixed Waste (open access)

Environmental Assessment Offsite Thermal Treatment of Low-Level Mixed Waste

The U.S. Department of Energy (DOE), Richland Operations Office (RL) needs to demonstrate the economics and feasibility of offsite commercial treatment of contact-handled low-level mixed waste (LLMW), containing polychlorinated biphenyls (PCBS) and other organics, to meet existing regulatory standards for eventual disposal.
Date: May 6, 1999
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Federal Courts: Differences Exist In Ordering Fines and Restitution (open access)

Federal Courts: Differences Exist In Ordering Fines and Restitution

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO provided information on federal offenders who were ordered to pay criminal fines and victim restitution, focusing on: (1) the percentage of offenders who were ordered to pay fines or restitution in fiscal year (FY) 1997 and those who were not; (2) differences across judicial circuits and districts in the percent of offenders who were ordered to pay fines or restitution and those who were not; and (3) officials' opinions about possible reasons for those differences."
Date: May 6, 1999
Creator: United States. General Accounting Office.
Object Type: Report
System: The UNT Digital Library
Federal Courts: Differences Exist in Ordering Fines and Restitution (open access)

Federal Courts: Differences Exist in Ordering Fines and Restitution

Testimony issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO provided information on federal courts and the differences that exist in ordering fines and restitution, focusing on: (1) the percentages of those offenders who were ordered to pay fines and restitution in fiscal year (FY) 1997 and those who were not; (2) differences across judicial circuits and districts in the percentages of those offenders who were ordered to pay fines or restitution and those who were not; and (3) officials' opinions about possible reasons for these differences."
Date: May 6, 1999
Creator: United States. General Accounting Office.
Object Type: Text
System: The UNT Digital Library
Fike MCO Pressure Safety Element (open access)

Fike MCO Pressure Safety Element

None
Date: May 6, 1999
Creator: Van Katwijk, Carl
Object Type: Report
System: The UNT Digital Library
Fisher SCHe pressure control valves 5*08 and 5*27 and 5*47 and 5*67 and 5*80 and 5*82 and 5*84 and 5*86 (open access)

Fisher SCHe pressure control valves 5*08 and 5*27 and 5*47 and 5*67 and 5*80 and 5*82 and 5*84 and 5*86

None
Date: May 6, 1999
Creator: Van Katwijk, Carl
Object Type: Report
System: The UNT Digital Library
Foster Care: Kinship Care Quality and Permanency Issues (open access)

Foster Care: Kinship Care Quality and Permanency Issues

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO reviewed how well kinship care is serving foster children, focusing on the: (1) quality of care that children in kinship care receive compared with that received by other foster children, as measured by a caseworker's assessment of a caregiver's parenting skills, the extent to which a foster child is able to maintain contact with familiar people and surroundings, and a caregiver's willingness to enforce court-ordered restrictions on parental visits; (2) frequency with which state child welfare agencies pursue various permanent living arrangements and the time children in kinship care have spent in the system compared with other foster children; and (3) recent state initiatives intended to help ensure that children in kinship care receive good quality foster care and are placed in permanent homes in a timely manner."
Date: May 6, 1999
Creator: United States. General Accounting Office.
Object Type: Report
System: The UNT Digital Library
Griswold Tempered Water Flow Regulator Valves Used as Anti Siphon Valves (open access)

Griswold Tempered Water Flow Regulator Valves Used as Anti Siphon Valves

None
Date: May 6, 1999
Creator: Van Katwijk, Carl
Object Type: Report
System: The UNT Digital Library
Krohne Flow Indicator and High Flow Alarm Local Indicator and High Flow Alarm of Helium Flow from the SCHe Purge Lines C and D to the Process Vent (open access)

Krohne Flow Indicator and High Flow Alarm Local Indicator and High Flow Alarm of Helium Flow from the SCHe Purge Lines C and D to the Process Vent

None
Date: May 6, 1999
Creator: Van Katwijk, Carl
Object Type: Report
System: The UNT Digital Library
Least-squares streamline diffusion finite element approximations to singularly perturbed convection-diffusion problems (open access)

Least-squares streamline diffusion finite element approximations to singularly perturbed convection-diffusion problems

In this paper we introduce and study a least-squares finite element approximation for singularly perturbed convection-diffusion equations of second order. By introducing the flux (diffusive plus convective) as a new unknown, the problem is written in a mixed form as a first order system. Further, the flux is augmented by adding the lower order terms with a small parameter. The new first order system is approximated by the least-squares finite element method using the minus one norm approach of Bramble, Lazarov, and Pasciak [2]. Further, we estimate the error of the method and discuss its implementation and the numerical solution of some test problems.
Date: May 6, 1999
Creator: Lazarov, R. D. & Vassilevski, P. S.
Object Type: Article
System: The UNT Digital Library
Massively Parallel Computing: A Sandia Perspective (open access)

Massively Parallel Computing: A Sandia Perspective

The computing power available to scientists and engineers has increased dramatically in the past decade, due in part to progress in making massively parallel computing practical and available. The expectation for these machines has been great. The reality is that progress has been slower than expected. Nevertheless, massively parallel computing is beginning to realize its potential for enabling significant break-throughs in science and engineering. This paper provides a perspective on the state of the field, colored by the authors' experiences using large scale parallel machines at Sandia National Laboratories. We address trends in hardware, system software and algorithms, and we also offer our view of the forces shaping the parallel computing industry.
Date: May 6, 1999
Creator: Dosanjh, Sudip S.; Greenberg, David S.; Hendrickson, Bruce; Heroux, Michael A.; Plimpton, Steve J.; Tomkins, James L. et al.
Object Type: Article
System: The UNT Digital Library
Measurement of Fracture Aperture Fields Using Ttransmitted Light: An Evaluation of Measurement Errors and their Influence on Simulations of Flow and Transport through a Single Fracture (open access)

Measurement of Fracture Aperture Fields Using Ttransmitted Light: An Evaluation of Measurement Errors and their Influence on Simulations of Flow and Transport through a Single Fracture

Understanding of single and multi-phase flow and transport in fractures can be greatly enhanced through experimentation in transparent systems (analogs or replicas) where light transmission techniques yield quantitative measurements of aperture, solute concentration, and phase saturation fields. Here we quanti@ aperture field measurement error and demonstrate the influence of this error on the results of flow and transport simulations (hypothesized experimental results) through saturated and partially saturated fractures. find that precision and accuracy can be balanced to greatly improve the technique and We present a measurement protocol to obtain a minimum error field. Simulation results show an increased sensitivity to error as we move from flow to transport and from saturated to partially saturated conditions. Significant sensitivity under partially saturated conditions results in differences in channeling and multiple-peaked breakthrough curves. These results emphasize the critical importance of defining and minimizing error for studies of flow and transpoti in single fractures.
Date: May 6, 1999
Creator: Detwiler, Russell L.; Glass, Robert J. & Pringle, Scott E.
Object Type: Article
System: The UNT Digital Library
Natural gas monthly, April 1999 (open access)

Natural gas monthly, April 1999

The Natural Gas Monthly (NGM) highlights activities, events, and analyses of interest to public and private sector organizations associated with the natural gas industry. Volume and price data are presented each month for natural gas production, distribution, consumption, and interstate pipeline activities. Producer-related activities and underground storage data are also reported. From time to time, the NGM features articles designed to assist readers in using and interpreting natural gas information. There are two feature articles in this issue: Natural gas 1998: Issues and trends, Executive summary; and Special report: Natural gas 1998: A preliminary summary. 6 figs., 28 tabs.
Date: May 6, 1999
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Neutron tube design study for boron neutron capture therapy application (open access)

Neutron tube design study for boron neutron capture therapy application

Radio-frequency (RF) driven ion sources are being developed in Lawrence Berkeley National Laboratory (LBNL) for sealed-accelerator-tube neutron generator application. By using a 5-cm-diameter RF-driven multicusp source H{sup +} yields over 95% have been achieved. These experimental findings will enable one to develop compact neutron generators based on the D-D or D-T fusion reactions. In this new neutron generator, the ion source, the accelerator and the target are all housed in a sealed metal container without external pumping. Recent moderator design simulation studies have shown that 14 MeV neutrons could be moderated to therapeutically useful energy ranges for boron neutron capture therapy (BNCT). The dose near the center of the brain with optimized moderators is about 65% higher than the dose obtained from a typical neutron spectrum produced by the Brookhaven Medical Research Reactor (BMRR), and is comparable to the dose obtained by other accelerator-based neutron sources. With a 120 keV and 1 A deuteron beam, a treatment time of {approx}35 minutes is estimated for BNCT.
Date: May 6, 1999
Creator: Verbeke, J. M.; Lee, Y.; Leung, K. N.; Vujic, J.; Williams, M. D.; Wu, L. K. et al.
Object Type: Article
System: The UNT Digital Library
A new approach in utilizing a computer data acquisition system for criticality safety control (open access)

A new approach in utilizing a computer data acquisition system for criticality safety control

A new approach in utilizing a computer data acquisition system is proposed to address many issues associated with criticality safety control. This Criticality Safety Support System (CSSS) utilizes many features of computer and information process technology such as digital pictures, barcodes, voice data entry, etc. to enhance criticality safety in an R and D environment. Due to on-line data retrieving, data recording, and data management offered by new technology, the CSSS would provide a framework to design new solutions to old problems. This pilot program is the first step in developing this application for the years to come.
Date: May 6, 1999
Creator: Hopkins, H; Song, H & Warren, F
Object Type: Article
System: The UNT Digital Library
Permeability Upscaling Measured on a Block of Berea Sandstone: Results and Interpretation (open access)

Permeability Upscaling Measured on a Block of Berea Sandstone: Results and Interpretation

To physically investigate permeability upscaling over 13,000 permeability values were measured with four different sample supports (i.e., sample volumes) on a block of Berea Sandstone. At each sample support spatially-exhaustive permeability data sets were measured, subject to consistent flow geometry and boundary conditions, with a specially adapted minipermeameter test system. Here, we present and analyze a subset of the data consisting of 2304 permeability values collected from a single block face oriented normal to stratification. Results reveal a number of distinct and consistent trends (i.e., upscaling) relating changes in key summary statistics to an increasing sample support. Examples include the sample mean and semivariogram range that increase with increasing sample support and the sample variance that decreases. To help interpret the measured mean upscaling we compared it to theoretical models that are only available for somewhat different flow geometries. The comparison suggests that the non-uniform flow imposed by the rninipermeameter coupled with permeability anisotropy at the scale of the local support (i.e., smallest sample support for which data is available) are the primary controls on the measured upscaling. This work demonstrates, experimentally, that it is not always appropriate to treat the local-support permeability as an intrinsic feature of the porous …
Date: May 6, 1999
Creator: Tidwell, Vincent C. & Wilson, John L.
Object Type: Article
System: The UNT Digital Library
PFP issues/assumptions development and management planning guide (open access)

PFP issues/assumptions development and management planning guide

The PFP Issues/Assumptions Development and Management Planning Guide presents the strategy and process used for the identification, allocation, and maintenance of an Issues/Assumptions Management List for the Plutonium Finishing Plant (PFP) integrated project baseline. Revisions to this document will include, as attachments, the most recent version of the Issues/Assumptions Management List, both open and current issues/assumptions (Appendix A), and closed or historical issues/assumptions (Appendix B). This document is intended be a Project-owned management tool. As such, this document will periodically require revisions resulting from improvements of the information, processes, and techniques as now described. Revisions that suggest improved processes will only require PFP management approval.
Date: May 6, 1999
Creator: SINCLAIR, J.C.
Object Type: Report
System: The UNT Digital Library
Quantum Kinematics of Bosonic Vortex Loops (open access)

Quantum Kinematics of Bosonic Vortex Loops

Poisson structure for vortex filaments (loops and arcs) in 2D ideal incompressible fluid is analyzed in detail. Canonical coordinates and momenta on coadjoint orbits of the area-preserving diffeomorphism group, associated with such vortices, are found. The quantum space of states in the simplest case of ''bosonic'' vortex loops is built within a geometric quantization approach to the description of a quantum fluid. Fock-like structure and non-local creation and annihilation operators of quantum vortex filaments are introduced.
Date: May 6, 1999
Creator: Goldin, G. A.; Owczarek, R. & Sharp, D. H.
Object Type: Article
System: The UNT Digital Library