International linear collider reference design report (open access)

International linear collider reference design report

The International Linear Collider will give physicists a new cosmic doorway to explore energy regimes beyond the reach of today's accelerators. A proposed electron-positron collider, the ILC will complement the Large Hadron Collider, a proton-proton collider at the European Center for Nuclear Research (CERN) in Geneva, Switzerland, together unlocking some of the deepest mysteries in the universe. With LHC discoveries pointing the way, the ILC -- a true precision machine -- will provide the missing pieces of the puzzle. Consisting of two linear accelerators that face each other, the ILC will hurl some 10 billion electrons and their anti-particles, positrons, toward each other at nearly the speed of light. Superconducting accelerator cavities operating at temperatures near absolute zero give the particles more and more energy until they smash in a blazing crossfire at the centre of the machine. Stretching approximately 35 kilometres in length, the beams collide 14,000 times every second at extremely high energies -- 500 billion-electron-volts (GeV). Each spectacular collision creates an array of new particles that could answer some of the most fundamental questions of all time. The current baseline design allows for an upgrade to a 50-kilometre, 1 trillion-electron-volt (TeV) machine during the second stage of …
Date: June 22, 2007
Creator: Aarons, G.
Object Type: Report
System: The UNT Digital Library
Progress on H5Part: A Portable High Performance Parallel DataInterface for Electromagnetics Simulations (open access)

Progress on H5Part: A Portable High Performance Parallel DataInterface for Electromagnetics Simulations

Significant problems facing all experimental andcomputationalsciences arise from growing data size and complexity. Commonto allthese problems is the need to perform efficient data I/O ondiversecomputer architectures. In our scientific application, thelargestparallel particle simulations generate vast quantitiesofsix-dimensional data. Such a simulation run produces data foranaggregate data size up to several TB per run. Motived by the needtoaddress data I/O and access challenges, we have implemented H5Part,anopen source data I/O API that simplifies the use of the HierarchicalDataFormat v5 library (HDF5). HDF5 is an industry standard forhighperformance, cross-platform data storage and retrieval that runsonall contemporary architectures from large parallel supercomputerstolaptops. H5Part, which is oriented to the needs of the particlephysicsand cosmology communities, provides support for parallelstorage andretrieval of particles, structured and in the future unstructuredmeshes.In this paper, we describe recent work focusing on I/O supportforparticles and structured meshes and provide data showing performance onmodernsupercomputer architectures like the IBM POWER 5.
Date: June 22, 2007
Creator: Adelmann, Andreas; Gsell, Achim; Oswald, Benedikt; Schietinger,Thomas; Bethel, Wes; Shalf, John et al.
Object Type: Article
System: The UNT Digital Library
A High Temperature Phase Transition in Weakly Coupled Large N Gauge Theories on a Three-sphere (open access)

A High Temperature Phase Transition in Weakly Coupled Large N Gauge Theories on a Three-sphere

We argue that weakly coupled 3+1 dimensional large N SU(N) gauge theories, with 't Hooft coupling {gamma}, compactified on a three-sphere of radius R, exhibit a novel second order phase transition at a temperature T{sub c} = C{radical}{gamma} R. The known constant C depends on the details of the gauge theory. The phase transition is characterized by a change in the eigenvalue distributions of the fields. Above the transition, the only eigenvalues which condense are those of the lowest Kaluza-Klein mode of the spatial gauge field Ai on the three-sphere. Below the transition the eigenvalues of the lowest Kaluza-Klein mode of an additional field condense. We discuss in particular the examples of pure Yang-Mills theory and of the N = 4 supersymmetric Yang-Mills theory.
Date: June 22, 2007
Creator: Aharony, Ofer & Hartnoll, Sean A.
Object Type: Report
System: The UNT Digital Library
Global Cooling: Effect of Urban Albedo on Global Temperature (open access)

Global Cooling: Effect of Urban Albedo on Global Temperature

In many urban areas, pavements and roofs constitute over 60% of urban surfaces (roof 20-25%, pavements about 40%). The roof and the pavement albedo can be increased by about 0.25 and 0.10, respectively, resulting in a net albedo increase for urban areas of about 0.1. Many studies have demonstrated building cooling-energy savings in excess of 20% upon raising roof reflectivity from an existing 10-20% to about 60%. We estimate U.S. potential savings in excess of $1 billion (B) per year in net annual energy bills. Increasing albedo of urban surfaces can reduce the summertime urban temperature and improve the urban air quality. Increasing the urban albedo has the added benefit of reflecting more of the incoming global solar radiation and countering the effect of global warming. We estimate that increasing albedo of urban areas by 0.1 results in an increase of 3 x 10{sup -4} in Earth albedo. Using a simple global model, the change in air temperature in lowest 1.8 km of the atmosphere is estimated at 0.01K. Modelers predict a warming of about 3K in the next 60 years (0.05K/year). Change of 0.1 in urban albedo will result in 0.01K global cooling, a delay of {approx}0.2 years in …
Date: May 22, 2007
Creator: Akbari, Hashem; Menon, Surabi & Rosenfeld, Arthur
Object Type: Article
System: The UNT Digital Library
Development of a Novel Catalyst for NO Decomposition (open access)

Development of a Novel Catalyst for NO Decomposition

Air pollution arising from the emission of nitrogen oxides as a result of combustion taking place in boilers, furnaces and engines, has increasingly been recognized as a problem. New methods to remove NO{sub x} emissions significantly and economically must be developed. The current technology for post-combustion removal of NO is the selective catalytic reduction (SCR) of NO by ammonia or possibly by a hydrocarbon such as methane. The catalytic decomposition of NO to give N{sub 2} will be preferable to the SCR process because it will eliminate the costs and operating problems associated with the use of an external reducing species. The most promising decomposition catalysts are transition metal (especially copper)-exchanged zeolites, perovskites, and noble metals supported on metal oxides such as alumina, silica, and ceria. The main shortcoming of the noble metal reducible oxide (NMRO) catalysts is that they are prone to deactivation by oxygen. It has been reported that catalysts containing tin oxide show oxygen adsorption behavior that may involve hydroxyl groups attached to the tin oxide. This is different than that observed with other noble metal-metal oxide combinations, which have the oxygen adsorbing on the noble metal and subsequently spilling over to the metal oxide. This observation …
Date: June 22, 2007
Creator: Akyurtlu, Ates & Akyurtlu, Jale F.
Object Type: Report
System: The UNT Digital Library
Semiclassical (SC) Description of Electronically Non-AdiabaticDynamics via the Initial Value Representation (IVR) (open access)

Semiclassical (SC) Description of Electronically Non-AdiabaticDynamics via the Initial Value Representation (IVR)

The initial value representation (IVR) of semiclassical (SC) theory is used in conjunction with the Meyer-Miller/Stock-Thoss description of electronic degrees of freedom in order to treat electronically non-adiabatic processes. It is emphasized that the classical equations of motion for the nuclear and electronic degrees of freedom that emerge in this description are precisely the Ehrenfest equations of motion (the force on the nuclei is the force averaged over the electronic wavefunction), but that the trajectories given by these equations of motion do not have the usual shortcomings of the traditional Ehrenfest model when they are used within the SC-IVR framework. For example, in the traditional Ehrenfest model (a mixed quantum-classical approach) the nuclear motion emerges from a non-adiabatic encounter on an average potential energy surface (a weighted average according to the population in the various electronic states), while the SC-IVR describes the correct correlation between electronic and nuclear dynamics, i.e., the nuclear motion is on one potential energy surface or the other depending on the electronic state. Calculations using forward-backward versions of SC-IVR theory (FB-IVR) are presented to illustrate this behavior. An even more approximate version of the SC-IVR, the linearized approximation (LSC-IVR), is slightly better than the traditional Ehrenfest …
Date: June 22, 2007
Creator: Ananth, V.; Venkataraman, C. & Miller, W. H.
Object Type: Article
System: The UNT Digital Library
Thermal Diffusivity and Conductivity Measurements in Diamond Anvil Cells (open access)

Thermal Diffusivity and Conductivity Measurements in Diamond Anvil Cells

We have undertaken a study of the feasibility of an innovative method for the determination of thermal properties of materials at extreme conditions. Our approach is essentiality an extension of the flash method to the geometry of the diamond-anvil cell and our ultimate goal is to greatly enlarge the pressure and temperature range over which thermal properties can be investigated. More specifically, we have performed test experiments to establish a technique for probing thermal diffusivity on samples of dimensions compatible with the physical constraints of the diamond anvil cell.
Date: February 22, 2007
Creator: Antonangeli, D & Farber, D L
Object Type: Report
System: The UNT Digital Library
Proton Form Factors Measurements in the Time-Like Region (open access)

Proton Form Factors Measurements in the Time-Like Region

I present an overview of the measurement of the proton form factors in the time-like region. BABAR has recently measured with great accuracy the e{sup +}e{sup -} {yields} p{bar p} reaction from production threshold up to an energy of {approx} 4.5 GeV, finding evidence for a ratio of the electric to magnetic form factor greater than unity, contrary to expectation. In agreement with previous measurements, BABAR confirmed the steep rise of the magnetic form factor close to the p{bar p} mass threshold, suggesting the possible presence of an under-threshold N{bar N} vector state. These and other open questions related to the nucleon form factors both in the time-like and space-like region, wait for more data with different experimental techniques to be possibly solved.
Date: October 22, 2007
Creator: Anulli, F.
Object Type: Article
System: The UNT Digital Library
Cleanup Verification Package for the 100-F-20, Pacific Northwest Laboratory Parallel Pits (open access)

Cleanup Verification Package for the 100-F-20, Pacific Northwest Laboratory Parallel Pits

This cleanup verification package documents completion of remedial action for the 100-F-20, Pacific Northwest Laboratory Parallel Pits waste site. This waste site consisted of two earthen trenches thought to have received both radioactive and nonradioactive material related to the 100-F Experimental Animal Farm.
Date: January 22, 2007
Creator: Appel, M. J.
Object Type: Report
System: The UNT Digital Library
Persistent Monitoring Platforms Final Report (open access)

Persistent Monitoring Platforms Final Report

This project was inspired and motivated by the need to provide better platforms for persistent surveillance. In the years since the inception of this work, the need for persistence of surveillance platforms has become even more widely appreciated, both within the defense community and the intelligence community. One of the most demanding technical requirements for such a platform involves the power plant and energy storage system, and this project concentrated almost exclusively on the technology associated with this system for a solar powered, high altitude, unmanned aircraft. An important realization for the feasibility of such solar powered aircraft, made at the outset of this project, was that thermal energy may be stored with higher specific energy density than for any other known practical form of rechargeable energy storage. This approach has proved to be extraordinarily fruitful, and a large number of spin-off applications of this technology were developed in the course of this project.
Date: February 22, 2007
Creator: Bennett, C L
Object Type: Report
System: The UNT Digital Library
An Exact SU(2) Symmetry and Persistent Spin Helix ina Spin-orbit Coupled System (open access)

An Exact SU(2) Symmetry and Persistent Spin Helix ina Spin-orbit Coupled System

Spin-orbit coupled systems generally break the spin rotation symmetry. However, for a model with equal Rashba and Dresselhauss coupling constant (the ReD model), and for the [110] Dresselhauss model, a new type of SU(2) spin rotation symmetry is discovered. This symmetry is robust against spin-independent disorder and interactions, and is generated by operators whose wavevector depends on the coupling strength. It renders the spin lifetime infinite at this wavevector, giving rise to a Persistent Spin Helix (PSH). We obtain the spin fluctuation dynamics at, and away, from the symmetry point, and suggest experiments to observe the PSH.
Date: January 22, 2007
Creator: Bernevig, B.A.; /Stanford U., Phys. Dept. /Santa Barbara, KITP; Orenstein, J.; /LBL, Berkeley /UC, Berkeley; Zhang, Shou-Cheng & /Stanford U., Phys. Dept.
Object Type: Article
System: The UNT Digital Library
Measurements of the intercombination and forbidden lines from helium-like ions in Tokamaks and Electron Beam Ion Traps (open access)

Measurements of the intercombination and forbidden lines from helium-like ions in Tokamaks and Electron Beam Ion Traps

The paper reviews the results from tokamak experiments for the line ratios x/w, y/w, and z/w from helium-like ions with Z in the range from 14 to 28. With exception of the DITE experiments, where these line ratios were found to be in agreement with theoretical predictions, all other tokamak experiments yielded values that were significantly larger than predicted. The reasons for these discrepancies are not yet understood. It is possible that radial profile effects were not properly taken into account in the majority of the tokamak experiments. The paper also gives a short historical review of the X-ray diagnostic developments and also presents very recent data from a new type of X-ray imaging crystal spectrometer, which records spatially resolved spectra with a spatial resolution of about 1 cm in the plasma. These new data can be Abel inverted, so that it will be possible to determine line ratios at each radial position in the plasma. Effects of radial profiles, which may have affected the chord-integrated measurements of the past, will thus be eliminated in the future.
Date: August 22, 2007
Creator: Bitter, M.; Hill, K. W.; Von Goeler, S.; Stodiek, W.; Beiersdorfer, P.; Rice, J. E. et al.
Object Type: Article
System: The UNT Digital Library
Summary (open access)

Summary

The first International GLAST Symposium was held at Stanford, with less than a year to launch. Recent advances in the TeV and MeV ranges augur well for GLAST making major discoveries in GeV astronomy. Expectations for observations of several source types and backgrounds are summarized, along with some remaining organizational challenges.
Date: October 22, 2007
Creator: Blandford, Roger
Object Type: Article
System: The UNT Digital Library
Proposal for Extending the UPC Memory Copy Library Functions andSupporting Extensions to GASNet, Version 2.0 (open access)

Proposal for Extending the UPC Memory Copy Library Functions andSupporting Extensions to GASNet, Version 2.0

This document outlines a proposal for extending UPC'spoint-to-point memcpy library with support for explicitly non-blockingtransfers, and non-contiguous (indexed and strided) transfers. Variousportions of this proposal could stand alone as independent extensions tothe UPC library. The designs presented here are heavily influenced byanalogous functionality which exists in other parallel communicationsystems, such as MPI, ARMCI, Titanium, and network hardware API's such asQuadrics elan, Infiniband vapi, IBM LAPI and Cray X-1. Each sectioncontains proposed extensions to the libraries in the UPC LanguageSpecification (section 7) and corresponding extensions to the GASNetcommunication system API.
Date: March 22, 2007
Creator: Bonachea, Dan
Object Type: Report
System: The UNT Digital Library
EVALUATION OF TUNGSTEN ISOTOPES IN THE FAST NEUTRON RANGE INCLUDING CROSS-SECTION COVARIANCE ESTIMATION. (open access)

EVALUATION OF TUNGSTEN ISOTOPES IN THE FAST NEUTRON RANGE INCLUDING CROSS-SECTION COVARIANCE ESTIMATION.

New evaluations for the tungsten isotopes {sup 180,182,183,184,186}W in the neutron energy range up to 60 MeV were produced. In the resonance range only minor adjustments to the resonance parameters were made due to a lack of adequate experimental data. Evaluations in the fast energy region were based on nuclear model calculations using the EMPIRE-2.19 code. Recently derived dispersive coupled-channel optical model potentials for W and Ta isotopes were instrumental to achieve a very good description of the available microscopic cross-section database. Model covariance data were generated with the Monte Carlo technique to produce a prior estimate for the covariance matrix. Experimental data were introduced through the GANDR system. The evaluated files were tested on selected fusion neutronics benchmarks and showed marked improvement compared to other existing evaluations.
Date: April 22, 2007
Creator: CAPOTE,R.; SIN, M.; TRKOV, A.; HERMAN, M.; CARLSON, B.V. & OBLOZINSKY, P.
Object Type: Article
System: The UNT Digital Library
EXTENSION OF THE NUCLEAR REACTION MODEL CODE EMPIRE TO ACTINIDES NUCLEAR DATA EVALUATION. (open access)

EXTENSION OF THE NUCLEAR REACTION MODEL CODE EMPIRE TO ACTINIDES NUCLEAR DATA EVALUATION.

Recent extensions and improvements of the EMPIRE code system are outlined. They add new capabilities to the code, such as prompt fission neutron spectra calculations using Hauser-Feshbach plus pre-equilibrium pre-fission spectra, cross section covariance matrix calculations by Monte Carlo method, fitting of optical model parameters, extended set of optical model potentials including new dispersive coupled channel potentials, parity-dependent level densities and transmission through numerically defined fission barriers. These features, along with improved and validated ENDF formatting, exclusive/inclusive spectra, and recoils make the current EMPIRE release a complete and well validated tool for evaluation of nuclear data at incident energies above the resonance region. The current EMPIRE release has been used in evaluations of neutron induced reaction files for {sup 232}Th and {sup 231,233}Pa nuclei in the fast neutron region at IAEA. Triple-humped fission barriers and exclusive pre-fission neutron spectra were considered for the fission data evaluation. Total, fission, capture and neutron emission cross section, average resonance parameters and angular distributions of neutron scattering are in excellent agreement with the available experimental data.
Date: April 22, 2007
Creator: CAPOTE,R.; SIN, M.; TRKOV, A.; HERMAN, M.; CARLSON, B.V. & OBLOZINSKY, P.
Object Type: Article
System: The UNT Digital Library
Cavity Microwave Searches for Cosmological Axions (open access)

Cavity Microwave Searches for Cosmological Axions

This chapter will cover the search for dark matter axions based on microwave cavity experiments proposed by Pierre Sikivie. We will start with a brief overview of halo dark matter and the axion as a candidate. The principle of resonant conversion of axions in an external magnetic field will be described as well as practical considerations in optimizing the experiment as a signal-to-noise problem. A major focus of this chapter will be the two complementary strategies for ultra-low noise detection of the microwave photons--the 'photon-as-wave' approach (i.e. conventional heterojunction amplifiers and soon to be quantum-limited SQUID devices), and 'photon-as-particle' (i.e. Rydberg-atom single-quantum detection). Experimental results will be presented; these experiments have already reached well into the range of sensitivity to exclude plausible axion models, for limited ranges of mass. The section will conclude with a discussion of future plans and challenges for the microwave cavity experiment.
Date: January 22, 2007
Creator: Carosi, G. & van Bibber, K.
Object Type: Book
System: The UNT Digital Library
First `Winged' and `X'-shaped Radio Source Candidates (open access)

First `Winged' and `X'-shaped Radio Source Candidates

A small number of double-lobed radio galaxies (17 from our own census of the literature) show an additional pair of low surface brightness ''wings'', thus forming an overall ''X''-shaped appearance. The origin of the wings in these radio sources is unclear. They may be the result of back-flowing plasma from the currently active radio lobes into an asymmetric medium surrounding the active nucleus, which would make these ideal systems in which to study thermal/non-thermal plasma interactions in extragalactic radio sources. Another possibility is that the wings are the aging radio lobes left over after a (rapid) realignment of the central supermassive black-hole/accretion disk system due perhaps to a merger. Generally, these models are not well tested; with the small number of known examples, previous works focused on detailed case studies of selected sources with little attempt at a systematic study of a large sample. Using the VLA-FIRST survey database, we are compiling a large sample of winged and X-shaped radio sources for such studies. As a first step toward this goal, an initial sample of 100 new candidate objects of this type are presented in this paper. The search process is described, optical identifications from available literature data, and basic …
Date: January 22, 2007
Creator: Cheung, C.C.
Object Type: Article
System: The UNT Digital Library
Extension of the Empire Code to the Resonance Region (open access)

Extension of the Empire Code to the Resonance Region

The preliminary version of a new module has been developed to be added to a nuclear reaction model code EMPIRE to allow for an evaluation of neutron cross sections in a resonance region. It automates most of the evaluation procedures and can be executed within EMPIRE or as a stand-alone program. The module includes a graphic user interface (GUI) and a number of codes and scripts that read individual, as well as average, resonance parameters from the Atlas of Neutron Resonances and other physical constants from RIPL-2, perform an analysis of the available resonances, carry out statistical distributions, and compute cross sections in resolved and unresolved resonance regions which are then compared with experimental data. The module also provides an ENDF-formatted file for a resonance region and various plots allowing for a verification of the procedure. The formatted file can be integrated later into the final ENDF-6 file as generated by the EMPIRE code. However, as a preliminary version, extensive testing and further improvements are needed before this new capability can be incorporated into the production version of EMPIRE.
Date: April 22, 2007
Creator: Cho, Y. S.; Herman, M.; Mughabghab, S. F.; Oblozinsky, P.; Rochman, D. & Lee, Y. O.
Object Type: Article
System: The UNT Digital Library
Review of Understanding the Micro to Macro Behaviour of Rock FluidSystems (open access)

Review of Understanding the Micro to Macro Behaviour of Rock FluidSystems

The book consists of a series of summaries of studies supported by the Natural Environmental Research Council's thematic program of the same name. The objective of this research initiative was to improve understanding and characterization of subsurface fluid flow over a wide range of spatial scales through field investigations, laboratory studies, and computer simulations of these processes.
Date: January 22, 2007
Creator: Cortis, A.; Dobson, P. F. & Liu, H. H.
Object Type: Article
System: The UNT Digital Library
ENSURING ADEQUATE SAFETY WHEN USING HYDROGEN AS A FUEL (open access)

ENSURING ADEQUATE SAFETY WHEN USING HYDROGEN AS A FUEL

Demonstration projects using hydrogen as a fuel are becoming very common. Often these projects rely on project-specific risk evaluations to support project safety decisions. This is necessary because regulations, codes, and standards (hereafter referred to as standards) are just being developed. This paper will review some of the approaches being used in these evolving standards, and techniques which demonstration projects can implement to bridge the gap between current requirements and stakeholder desires. Many of the evolving standards for hydrogen-fuel use performance-based language, which establishes minimum performance and safety objectives, as compared with prescriptive-based language that prescribes specific design solutions. This is being done for several reasons including: (1) concern that establishing specific design solutions too early will stifle invention, (2) sparse performance data necessary to support selection of design approaches, and (3) a risk-adverse public which is unwilling to accept losses that were incurred in developing previous prescriptive design standards. The evolving standards often contain words such as: ''The manufacturer shall implement the measures and provide the information necessary to minimize the risk of endangering a person's safety or health''. This typically implies that the manufacturer or project manager must produce and document an acceptable level of risk. If accomplished …
Date: January 22, 2007
Creator: Coutts, D
Object Type: Article
System: The UNT Digital Library
Photonic Crystal Laser-Driven Accelerator Structures (open access)

Photonic Crystal Laser-Driven Accelerator Structures

Laser-driven acceleration holds great promise for significantly improving accelerating gradient. However, scaling the conventional process of structure-based acceleration in vacuum down to optical wavelengths requires a substantially different kind of structure. We require an optical waveguide that (1) is constructed out of dielectric materials, (2) has transverse size on the order of a wavelength, and (3) supports a mode with speed-of-light phase velocity in vacuum. Photonic crystals---structures whose electromagnetic properties are spatially periodic---can meet these requirements. We discuss simulated photonic crystal accelerator structures and describe their properties. We begin with a class of two-dimensional structures which serves to illustrate the design considerations and trade-offs involved. We then present a three-dimensional structure, and describe its performance in terms of accelerating gradient and efficiency. We discuss particle beam dynamics in this structure, demonstrating a method for keeping a beam confined to the waveguide. We also discuss material and fabrication considerations. Since accelerating gradient is limited by optical damage to the structure, the damage threshold of the dielectric is a critical parameter. We experimentally measure the damage threshold of silicon for picosecond pulses in the infrared, and determine that our structure is capable of sustaining an accelerating gradient of 300 MV/m at 1550 …
Date: August 22, 2007
Creator: Cowan, Benjamin M.
Object Type: Report
System: The UNT Digital Library
EVALUATION OF FLOWSHEET CHANGES FOR THE HIGHLY ENRICHED URANIUM BLENDDOWN PROGRAM (open access)

EVALUATION OF FLOWSHEET CHANGES FOR THE HIGHLY ENRICHED URANIUM BLENDDOWN PROGRAM

H Canyon is considering a flowsheet change for Plutonium (Pu) Contaminated Scrap (PuCS) material. The proposed change is to route dissolved PuCS material directly to a uranium (U) storage tank. As a result, the PuCS solution will bypass Head End and First U Cycle, and will be purified by solvent extraction in Second U Cycle. The PuCS solution contains appreciable amounts of boron (B) and fluoride (F{sup -}), which are currently at trace levels in the U storage tank. Though unlikely, if the B concentration in the U storage tank were to reach 1.8 g B/g U, the entire contents of the U storage tank would likely require a second pass through Second U Cycle to provide sufficient decontamination to meet the Tennessee Valley Authority (TVA) Blend Grade Highly Enriched Uranium (HEU) specification for B, which is 30 {micro}g/g U. In addition, Second U Cycle is expected to provide sufficient decontamination of F{sup -} and Pu regardless of the amount of PuCS solution sent to the storage tank. Though aluminum (Al) is not present in the PuCS solution, B can be credited as a complexant of F{sup -}. Both stability constants from the literature and Savannah River National Laboratory (SRNL) …
Date: October 22, 2007
Creator: Crowder, M.; Rudisill, T.; Laurinat, J. & Mickalonis, J.
Object Type: Article
System: The UNT Digital Library
Performance-Driven Interface Contract Enforcement for Scientific Components (open access)

Performance-Driven Interface Contract Enforcement for Scientific Components

Several performance-driven approaches to selectively enforce interface contracts for scientific components are investigated. The goal is to facilitate debugging deployed applications built from plug-and-play components while keeping the cost of enforcement within acceptable overhead limits. This paper describes a study of global enforcement using a priori execution cost estimates obtained from traces. Thirteen trials are formed from five, single-component programs. Enforcement experiments conducted using twenty-three enforcement policies are used to determine the nature of exercised contracts and the impact of a variety of sampling strategies. Performance-driven enforcement appears to be best suited to programs that exercise moderately expensive contracts.
Date: February 22, 2007
Creator: Dahlgren, Tamara L.
Object Type: Article
System: The UNT Digital Library