A Reference-Dependent Regret Model for Deterministic Trade-off Studies (open access)

A Reference-Dependent Regret Model for Deterministic Trade-off Studies

Today's typical multi-criteria decision analysis is based on classical expected utility theory that assumes a mythical ''Rational Individual'' immune to psychological influences such as anticipated regret. It is therefore in conflict with rational individuals who trade-off some benefits and forgo the alternative with the highest total classical utility for a more balanced alternative in order to reduce their levels of anticipated regret. This paper focuses on decision making under certainty. It presents a reference-dependent regret model (RDRM) in which the level of regret that an individual experiences depends on the absolute values rather than the differences of the utilities of the chosen and forgone alternatives. The RDRM best choice may differ from the conventional linear additive utility model, the analytic hierarchy process, and the regret theory of Bell and Loomes and Sugden. Examples are presented that indicate that RDRM is the better predictive descriptor for decision making under certainty. RDRM satisfies transitivity of the alternatives under pairwise comparisons and models rank reversal consistent with observed reasonable choices under dynamic or distinct situations. Like regret theory, the RDRM utilities of all the alternatives under consideration are interrelated. For complex trade-off studies regret is incorporated as an element of a cost-utility-regret analysis …
Date: February 25, 2005
Creator: Kujawski, Edouard
System: The UNT Digital Library
LCLS X-Ray FEL Output Performance in the Presence of HighlyTime-Dependent Undulator Wakefields (open access)

LCLS X-Ray FEL Output Performance in the Presence of HighlyTime-Dependent Undulator Wakefields

Energy loss due to wakefields within a long undulator, if not compensated by an appropriate tapering of the magnetic field strength, can degrade the FEL process by detuning the resonant FEL frequency. The wakefields arise from the vacuum chamber wall resistivity, its surface roughness, and abrupt changes in its aperture. For LCLS parameters, the resistive-wall component is the most critical and depends upon the chamber material (e.g., Cu) and its radius. Of recent interest[1] is the so-called ''AC'' component of the resistive-wall wake which can lead to strong variations on very short timescales (e.g., {approx} 20 0fs). To study the expected performance of the LCLS in the presence of these wakefields, we have made an extensive series of start-to-end SASE simulations with tracking codes PARMELA and ELEGANT, and time-dependent FEL simulation codes GENESIS1.3 and GINGER. We discuss the impact of the wakefield losses upon output energy, spectral bandwidth, and temporal envelope of the output FEL pulse, as well as the benefits of a partial compensation of the time-dependent wake losses obtained with a slight z-dependent taper in the undulator field. We compare the taper results to those predicted analytically[2].
Date: August 25, 2005
Creator: Bane, Karl L. F.; Emma, Paul; Huang, Heinz-Dieter Nuhn; Stupakov, Gennady; Fawley, William M. & Reiche, Sven
System: The UNT Digital Library
Risk-Based Radionuclide Derived Concentration Guideline Levels For An Industrial Worker Exposed To Concrete-Slab End States At The Savannah River Site (open access)

Risk-Based Radionuclide Derived Concentration Guideline Levels For An Industrial Worker Exposed To Concrete-Slab End States At The Savannah River Site

Dose and risk assessments are an integral part of decommissioning activities. Most human health risk assessments are performed for a reasonable maximum exposure to an individual with assumed intake and exposure parameters that depend on the end state of the decommissioning activities and the likely future use of the site. Regardless of how the potentially exposed individual is defined, the subsequent calculated human health risk is not a measurable quantity. To demonstrate compliance with risk-based acceptance or cleanliness criteria, facility-specific risk assessments usually are performed after final-verification sampling and analysis. Alternatively, conservative, a priori, guideline concentrations for residual contaminants can be calculated and rapidly compared to the subsequently measured contaminant concentrations to demonstrate compliance. In response to the request for accelerated cleanup at U.S. Department of Energy facilities, the Savannah River Site (SRS) is decommissioning its excess facilities through removal of the facility structures leaving only the concrete-slab foundations in place. Site-specific, risk-based derived concentration guideline levels (DCGLs) for radionuclides have been determined for a future industrial worker potentially exposed to residual contamination on these concrete slabs. When appropriate, these conservative DCGLs will be used at SRS in lieu of facility-specific risk assessments to further accelerate the decommissioning process. This …
Date: April 25, 2005
Creator: GERALD, JANNIK
System: The UNT Digital Library
Performance of a Block Structured, Hierarchical Adaptive MeshRefinement Code on the 64k Node IBM BlueGene/L Computer (open access)

Performance of a Block Structured, Hierarchical Adaptive MeshRefinement Code on the 64k Node IBM BlueGene/L Computer

We describe the performance of the block-structured Adaptive Mesh Refinement (AMR) code Raptor on the 32k node IBM BlueGene/L computer. This machine represents a significant step forward towards petascale computing. As such, it presents Raptor with many challenges for utilizing the hardware efficiently. In terms of performance, Raptor shows excellent weak and strong scaling when running in single level mode (no adaptivity). Hardware performance monitors show Raptor achieves an aggregate performance of 3:0 Tflops in the main integration kernel on the 32k system. Results from preliminary AMR runs on a prototype astrophysical problem demonstrate the efficiency of the current software when running at large scale. The BG/L system is enabling a physics problem to be considered that represents a factor of 64 increase in overall size compared to the largest ones of this type computed to date. Finally, we provide a description of the development work currently underway to address our inefficiencies.
Date: April 25, 2005
Creator: Greenough, Jeffrey A.; de Supinski, Bronis R.; Yates, Robert K.; Rendleman, Charles A.; Skinner, David; Beckner, Vince et al.
System: The UNT Digital Library
Meson Correlation Functions at High Temperatures. (open access)

Meson Correlation Functions at High Temperatures.

We present preliminary results for the correlation- and spectral functions of different meson channels on the lattice. The main focus lies on gaining control over cut-off as well as on the finite-volume effects. Extrapolations of screening masses above the deconfining temperature are guided by the result of the free (T = {infinity}) case on the lattice and in the continuum. We study the quenched non-perturbatively improved Wilson-clover fermion as well as the hypercube fermion action which might show less cut-off effects.
Date: July 25, 2005
Creator: Wissel, S.; Datta, S.; Karsch, F.; Laermann, E. & Shcheredin, S.
System: The UNT Digital Library
STATIC QUARK ANTI-QUARK FREE AND INTERNAL ENERGY IN 2-FLAVOR QCD AND BOUND STATES IN THE QGP. (open access)

STATIC QUARK ANTI-QUARK FREE AND INTERNAL ENERGY IN 2-FLAVOR QCD AND BOUND STATES IN THE QGP.

We present results on heavy quark free energies in 2-flavour QCD. The temperature dependence of the interaction between static quark anti-quark pairs will be analyzed in terms of temperature dependent screening radii, which give a first estimate on the medium modification of (heavy quark) bound states in the quark gluon plasma. Comparing those radii to the (zero temperature) mean squared charge radii of chasmonium states indicates that the J/{Psi} may survive the phase transition as a bound state, while {chi}{sub c} and {Psi}{prime} are expected to show significant thermal modifications at temperatures close to the transition. Furthermore we will analyze the relation between heavy quark free energies, entropy contributions and internal energy and discuss their relation to potential models used to analyze the melting of heavy quark bound states above the deconfinement temperature. Results of different groups and various potential models for bound states in the deconfined phase of QCD are compared.
Date: July 25, 2005
Creator: ZANTOW, F. & KACZMAREK, O.
System: The UNT Digital Library
The Qcd Phase Diagram at Finite Density. (open access)

The Qcd Phase Diagram at Finite Density.

We study the density of states method to explore the phase diagram of the chiral transition on the temperature and quark chemical potential plane. Four quark flavours are used in the analysis. Though the method is quite expensive small lattices show an indication for a triple-point connecting three different phases on the phase diagram.
Date: July 25, 2005
Creator: Schmidt, C.; Fodor, Z. & Katz, S.
System: The UNT Digital Library
HEAVY QUARK FREE ENERGIES AND SCREENING AT FINITE TEMPERATURE AND DENSITY. (open access)

HEAVY QUARK FREE ENERGIES AND SCREENING AT FINITE TEMPERATURE AND DENSITY.

We study the free energies of heavy quarks calculated from Polyakov loop correlation functions in full 2-flavour QCD using the p4-improved staggered fermion action. A small but finite baryon number density is included via Taylor expansion of the fermion determinant in the baryo-chemical potential {mu}. For temperatures above T{sub c} we extract Debye screening masses from the large distance behavior of the free energies and compare their {mu}-dependence to perturbative results.
Date: July 25, 2005
Creator: Doring, M.; Ejiri, S.; Kaczmarek, O.; Karsch, F. & Laermann, E.
System: The UNT Digital Library
Introduction to the HPC Challenge Benchmark Suite (open access)

Introduction to the HPC Challenge Benchmark Suite

The HPC Challenge benchmark suite has been released by the DARPA HPCS program to help define the performance boundaries of future Petascale computing systems. HPC Challenge is a suite of tests that examine the performance of HPC architectures using kernels with memory access patterns more challenging than those of the High Performance Linpack (HPL) benchmark used in the Top500 list. Thus, the suite is designed to augment the Top500 list, providing benchmarks that bound the performance of many real applications as a function of memory access characteristics e.g., spatial and temporal locality, and providing a framework for including additional tests. In particular, the suite is composed of several well known computational kernels (STREAM, HPL, matrix multiply--DGEMM, parallel matrix transpose--PTRANS, FFT, RandomAccess, and bandwidth/latency tests--b{sub eff}) that attempt to span high and low spatial and temporal locality space. By design, the HPC Challenge tests are scalable with the size of data sets being a function of the largest HPL matrix for the tested system.
Date: April 25, 2005
Creator: Luszczek, Piotr; Dongarra, Jack J.; Koester, David; Rabenseifner,Rolf; Lucas, Bob; Kepner, Jeremy et al.
System: The UNT Digital Library
Genomes, Phylogeny, and Evolutionary Systems Biology (open access)

Genomes, Phylogeny, and Evolutionary Systems Biology

With the completion of the human genome and the growing number of diverse genomes being sequenced, a new age of evolutionary research is currently taking shape. The myriad of technological breakthroughs in biology that are leading to the unification of broad scientific fields such as molecular biology, biochemistry, physics, mathematics and computer science are now known as systems biology. Here I present an overview, with an emphasis on eukaryotes, of how the postgenomics era is adopting comparative approaches that go beyond comparisons among model organisms to shape the nascent field of evolutionary systems biology.
Date: March 25, 2005
Creator: Medina, Monica
System: The UNT Digital Library
Optimization Studies of the FERMI at ELETTRA FEL Design (open access)

Optimization Studies of the FERMI at ELETTRA FEL Design

The FERMI at ELETTRA project at Sincotrone Trieste involves two FEL's, each based upon the principle of seeded harmonic generation and using the existing ELETTRA injection linac at 1.2 GeV beam energy. Scheduled to be completed in 2008, FEL-1 will operate in 40-100 nm wavelength range and will involve one stage of harmonic up-conversion. The second undulator line, FEL-2, will begin operation two years later in the 10-40 nm wavelength range and use two harmonic stages operating as a cascade. The FEL design assumes continuous wavelength tunability over the full wavelength range, and polarization tunability of the output radiation including vertical or horizontal linear as well as helical polarization. The design considers focusing properties and segmentation of realizable undulators and available input seed lasers. We review the studies that have led to our current design. We present results of simulations using GENESIS and GINGER simulation codes including studies of various shot-to-shot fluctuations and undulator errors. Findings for the expected output radiation in terms of the power, transverse and longitudinal coherence are reported.
Date: August 25, 2005
Creator: De Ninno, Giovanni; Fawley, William M.; Penn, Gregory E. & Graves,William
System: The UNT Digital Library
Assessment of Distributed Generation Potential in JapaneseBuildings (open access)

Assessment of Distributed Generation Potential in JapaneseBuildings

To meet growing energy demands, energy efficiency, renewable energy, and on-site generation coupled with effective utilization of exhaust heat will all be required. Additional benefit can be achieved by integrating these distributed technologies into distributed energy resource (DER) systems (or microgrids). This research investigates a method of choosing economically optimal DER, expanding on prior studies at the Berkeley Lab using the DER design optimization program, the Distributed Energy Resources Customer Adoption Model (DER-CAM). DER-CAM finds the optimal combination of installed equipment from available DER technologies, given prevailing utility tariffs, site electrical and thermal loads, and a menu of available equipment. It provides a global optimization, albeit idealized, that shows how the site energy loads can be served at minimum cost by selection and operation of on-site generation, heat recovery, and cooling. Five prototype Japanese commercial buildings are examined and DER-CAM applied to select the economically optimal DER system for each. The five building types are office, hospital, hotel, retail, and sports facility. Based on the optimization results, energy and emission reductions are evaluated. Furthermore, a Japan-U.S. comparison study of policy, technology, and utility tariffs relevant to DER installation is presented. Significant decreases in fuel consumption, carbon emissions, and energy costs …
Date: May 25, 2005
Creator: Zhou, Nan; Marnay, Chris; Firestone, Ryan; Gao, Weijun & Nishida,Masaru
System: The UNT Digital Library
GAUGE INVARIANCE IN A Z2 HAMILTONIAN LATTICE GUAGE THEORY. (open access)

GAUGE INVARIANCE IN A Z2 HAMILTONIAN LATTICE GUAGE THEORY.

We propose an efficient variational method for Z{sub 2} lattice gauge theory based on the matrix product ansatz. The method is applied to ladder and square lattices. The Gauss law needs to be imposed on quantum states to guarantee gauge invariance when one studies gauge theory in hamiltonian formalism. On the ladder lattice, we identify gauge invariant low-lying states by evaluating expectation values of the Gauss law operator after numerical diagonalization of the gauge hamiltonian. On the square lattice, the second order phase transition is well reproduced.
Date: July 25, 2005
Creator: SUGIHARA, T.
System: The UNT Digital Library
Utility Integrated Resource Planning: An Emerging Driver of NewRenewable Generation in the Western United States (open access)

Utility Integrated Resource Planning: An Emerging Driver of NewRenewable Generation in the Western United States

In the United States, markets for renewable generation--especially wind power--have grown substantially in recent years. This growth is typically attributed to technology improvements and resulting cost reductions, the availability of federal tax incentives, and aggressive state policy efforts. But another less widely recognized driver of new renewable generation is poised to play a major role in the coming years: utility integrated resource planning (IRP). Common in the late-1980s to mid-1990s, but relegated to lesser importance as many states took steps to restructure their electricity markets in the late-1990s, IRP has re-emerged in recent years as an important tool for utilities and regulators, particularly in regions such as the western United States, where retail competition has failed to take root. As practiced in the United States, IRP is a formal process by which utilities analyze the costs, benefits, and risks of all resources available to them--both supply- and demand-side--with the ultimate goal of identifying a portfolio of resources that meets their future needs at lowest cost and/or risk. Though the content of any specific utility IRP is unique, all are built on a common basic framework: (1) development of peak demand and load forecasts; (2) assessment of how these forecasts compare …
Date: September 25, 2005
Creator: Bolinger, Mark & Wiser, Ryan
System: The UNT Digital Library
On Viscosity, Conduction and Sound Waves in the Intracluster Medium (open access)

On Viscosity, Conduction and Sound Waves in the Intracluster Medium

None
Date: January 25, 2005
Creator: Fabian, A. C.; Reynolds, C. S.; Taylor, G. B. & Dunn, R. J. H.
System: The UNT Digital Library
Reactivity of Resorcinol Formaldehyde Resin with Nitric Acid (open access)

Reactivity of Resorcinol Formaldehyde Resin with Nitric Acid

Solid-state infrared spectroscopy, differential scanning calorimetry, and elemental analysis have been used to evaluate the reactivity of resorcinol formaldehyde resin with nitric acid and characterize the solid product. Two distinct reactions were identified within the temperature range 25-55 C. The first reaction is primarily associated with resin nitration, while the second involves bulk oxidation and degradation of the polymer network leading to dissolution and off-gassing. The threshold conditions promoting reaction have been identified. Reaction was confirmed with nitric acid concentrations as low as 3 M at 25 C applied temperature and 0.625 M at 66 C. Although a nitrated resin product can be isolated under appropriate experimental conditions, calorimetry testing indicates no significant hazard associated with handling the dry material.
Date: October 25, 2005
Creator: King, William D.; Fondeur, Fernando F.; Wilmarth, William R. & Pettis, Myra E.
System: The UNT Digital Library
Direct Conversion of Chemically De-Ashed Coal in Fuel Cells (II) (open access)

Direct Conversion of Chemically De-Ashed Coal in Fuel Cells (II)

We review the technical challenges associated with the production and use of various coal chars in a direct carbon conversion fuel cell. Existing chemical and physical deashing processes remove material below levels impacting performance at minimal cost. At equilibrium, sulfur entrained is rejected from the melt as COS in the offgas.
Date: July 25, 2005
Creator: Cooper, J F
System: The UNT Digital Library
THERMAL COOK-OFF EXPERIMENTS OF THE HMX BASED HIGH EXPLOSIVE LX-04 TO CHARACTERIZE VIOLENCE WITH VARYING CONFINEMENT (open access)

THERMAL COOK-OFF EXPERIMENTS OF THE HMX BASED HIGH EXPLOSIVE LX-04 TO CHARACTERIZE VIOLENCE WITH VARYING CONFINEMENT

Thermal cook-off experiments were carried out using LX-04 explosive (85% HMX and 15% Viton by weight) with different levels of confinement to characterize the effect of confinement on the reaction violence. These experiments involved heating a porous LX-04 sample in a stainless steel container with varying container end plate thickness and assembly bolt diameter to control overall confinement. As expected, detonation did not occur and reducing the overall confinement lowered the reaction violence. This is consistent with modeling results that predict that a lower confinement will act to lower the cook-off pressure and thus the overall burn rate which lowers the overall violence. These results suggest that controlling the overall system confinement can modify the relative safety in a given scenario.
Date: July 25, 2005
Creator: Garcia, F; Vandersall, K S; Forbes, J W; Tarver, C M & Greenwood, D
System: The UNT Digital Library
A Mountain-Scale Thermal Hydrologic Model for Simulating FluidFlow and Heat Transfer in Unsaturated Fractured Rock (open access)

A Mountain-Scale Thermal Hydrologic Model for Simulating FluidFlow and Heat Transfer in Unsaturated Fractured Rock

A multidimensional, mountain-scale, thermal-hydrologic (TH) numerical model is presented for investigating unsaturated flow behavior in response to decay heat from the radioactive waste repository in the Yucca Mountain unsaturated zone (UZ), Nevada. The model, consisting of both two-dimensional (2-D) and three-dimensional (3-D) representations of the UZ repository system, is based on the current repository design, drift layout, thermal loading scenario, and estimated current and future climate conditions. This mountain-scale TH model evaluates the coupled TH processes related to mountain-scale UZ flow. It also simulates the impact of radioactive waste heat release on the natural hydrogeological system, including heat-driven processes occurring near and far away from the emplacement tunnels or drifts. The model simulations predict thermally perturbed liquid saturation, gas- and liquid-phase fluxes, and water and rock temperature elevations, as well as the changes in water flux driven by evaporation/condensation processes and drainage between drifts. These simulations provide mountain-scale thermally perturbed flow fields for assessing the repository performance under thermal loading conditions.
Date: May 25, 2005
Creator: Wu, Yu-Shu; Mukhopadhyay, Sumit; Zhang, Keni & Bodvarsson,Gudmundur S.
System: The UNT Digital Library
Emittance Dilution due to Dipole Mode Rotating and Coupling in the Main Linacs of the ILC (open access)

Emittance Dilution due to Dipole Mode Rotating and Coupling in the Main Linacs of the ILC

The progress of multiple bunches of charged particles down the main L-band linacs of the ILC (International Linear Collider) can be disrupted by wakefields. These wakefields correspond to the electromagnetic fields excited in the accelerating cavities and have both long-range and short-range components. The horizontal and vertical modal components of the wakefield will be excited at slightly different frequencies (the dipole mode frequency degeneracy's are split) due to inevitable manufacturing errors. We simulate the progress of the ILC beam down the collider under the influence of these wakefields. In particular, we investigate the consequences on the final emittance dilution of the beam of coupling of the horizontal to the vertical motion of the beam.
Date: May 25, 2005
Creator: Jones, R. M. & Miller, R. H.
System: The UNT Digital Library
Synthesis and Electrochemical Characterization of M2Mn3O8 (M=Ca,Cu) Compounds and Derivatives (open access)

Synthesis and Electrochemical Characterization of M2Mn3O8 (M=Ca,Cu) Compounds and Derivatives

M{sub 2}Mn{sub 3}O{sub 8} (M=Ca{sup 2+}, Cu{sup 2+}) compounds were synthesized and characterized in lithium cells. The M{sup 2+} cations, which reside in the van der Waal's gaps between adjacent sheets of Mn{sub 3}O{sub 8}{sup 4-}, may be replaced chemically (by ion-exchange) or electrochemically with Li. More than 7 Li{sup +}/Cu{sub 2}Mn{sub 3}O{sub 8} may be inserted electrochemically, with concomitant reduction of Cu{sup 2+} to Cu metal, but less Li can be inserted into Ca{sub 2}Mn{sub 3}O{sub 8}. In the case of Cu{sup 2+}, this process is partially reversible when the cell is charged above 3.5 V vs. Li, but intercalation of Cu{sup +} rather than Cu{sup 2+} and Li{sup +}/Cu{sup +} exchange occurs during the subsequent discharge. If the cell potential is kept below 3.4 V, the Li in excess of 4Li{sup +}/Cu{sub 2}Mn{sub 3}O{sub 8} can be cycled reversibly. The unusual mobility of +2 cations in a layered structure has important implications both for the design of cathodes for Li batteries and for new systems that could be based on M{sup 2+} intercalation compounds.
Date: August 25, 2005
Creator: Park, Yong Joon & Doeff, Marca M.
System: The UNT Digital Library
Beryllium Sampling and Analysis Within the DOE Complex and Opportunities for Standardization (open access)

Beryllium Sampling and Analysis Within the DOE Complex and Opportunities for Standardization

Since the U. S. Department of Energy (DOE) published the DOE Beryllium Rule (10 CFR 850) in 1999, DOE sites have been required to measure beryllium on air filters and wipes for worker protection and for release of materials from beryllium-controlled areas. Measurements in the nanogram range on a filter or wipe are typically required. Industrial hygiene laboratories have applied methods from various analytical compendia, and a number of issues have emerged with sampling and analysis practices. As a result, a committee of analytical chemists, industrial hygienists, and laboratory managers was formed in November 2003 to address the issues. The committee developed a baseline questionnaire and distributed it to DOE sites and other agencies in the U.S. and U.K. The results of the questionnaire are presented in this paper. These results confirmed that a wide variety of practices were in use in the areas of sampling, sample preparation, and analysis. Additionally, although these laboratories are generally accredited by the American Industrial Hygiene Association (AIHA), there are inconsistencies in performance among accredited labs. As a result, there are significant opportunities for development of standard methods that could improve consistency. The current availabilities and needs for standard methods are further discussed in …
Date: January 25, 2005
Creator: BRISSON, MICHAEL
System: The UNT Digital Library
An Optimized Low-Charge Configuration of the LINAC Coherent Light Source (open access)

An Optimized Low-Charge Configuration of the LINAC Coherent Light Source

None
Date: May 25, 2005
Creator: Emma, P.; Huang, Z.; Limborg-Deprey, C.; Wu, J.; /SLAC; Fawley, W. et al.
System: The UNT Digital Library
Dual Power Supplies for PEP-II Injection Kickers (open access)

Dual Power Supplies for PEP-II Injection Kickers

Originally the PEP-II injection kickers were powered by one power supply. Since the kicker magnets where not perfectly matched, the stored beam got excited by about 7% of the maximum kicker amplitude. This led to luminosity losses which were especially obvious for trickle injection when the detector is on for data taking. Therefore two independent power supplies with thyratrons in the tunnel next to the kicker magnet were installed. This also reduces the necessary power by about a factor of four since there are no long cables that have to be charged. The kickers are now independently adjustable to eliminate any non-closure of the kicker system and therefore excitation of the stored beam. Setup, commissioning and fine tuning of this system are discussed.
Date: May 25, 2005
Creator: Olszewski, J; Decker, F.-J.; Iverson, R.H.; Kulikov, A.; Pappas, C. & /SLAC
System: The UNT Digital Library