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Firewall Architectures for High-Speed Networks: Final Report
Firewalls are a key component for securing networks that are vital to government agencies and private industry. They enforce a security policy by inspecting and filtering traffic arriving or departing from a secure network. While performing these critical security operations, firewalls must act transparent to legitimate users, with little or no effect on the perceived network performance (QoS). Packets must be inspected and compared against increasingly complex rule sets and tables, which is a time-consuming process. As a result, current firewall systems can introduce significant delays and are unable to maintain QoS guarantees. Furthermore, firewalls are susceptible to Denial of Service (DoS) attacks that merely overload/saturate the firewall with illegitimate traffic. Current firewall technology only offers a short-term solution that is not scalable; therefore, the \textbf{objective of this DOE project was to develop new firewall optimization techniques and architectures} that meet these important challenges. Firewall optimization concerns decreasing the number of comparisons required per packet, which reduces processing time and delay. This is done by reorganizing policy rules via special sorting techniques that maintain the original policy integrity. This research is important since it applies to current and future firewall systems. Another method for increasing firewall performance is with new …
Date:
August 20, 2007
Creator:
Fulp, Errin W.
Object Type:
Report
System:
The UNT Digital Library
Synthesis of Dihydropyridines and Pyridines from Imines and Alkynes via C-H Activation
A convenient one-pot C-H alkenylation/electrocyclization/aromatization sequence has been developed for the synthesis of highly substituted pyridine derivatives from alkynes and {alpha},{beta}-unsaturated N-benzyl aldimines and ketimines that proceeds through dihydropyridine intermediates. A new class of ligands for C-H activation was developed, providing broader scope for the alkenylation step than could be achieved with previously reported ligands. Substantial information was obtained about the mechanism of the reaction. This included the isolation of a C-H activated complex and its structure determination by X-ray analysis; in addition, kinetic simulations using the Copasi software were employed to determine rate constants for this transformation, implicating facile C-H oxidative addition and slow reductive elimination steps.
Date:
November 20, 2007
Creator:
Ellman, Jonathan A.; Colby, Denise & Bergman, Robert
Object Type:
Article
System:
The UNT Digital Library
CH3-ReO3 on gamma-Al2O3: understanding its structure, initiation,and reactivity in olefin metathesis
Me-ReO3 on gamma-alumina: understanding the structure, theinitiation and thereactivity of a highly active olefin metathesiscatalyst Heterolytic splitting of the C-H bond of the methyl group ofCH3ReO3 on AlsO reactive sites of alumina as a way to generate the activesite of CH3ReO3 supported on gamma-Al203.
Date:
January 20, 2007
Creator:
Salameh, Alain; Joubert, Jerome; Baudouin, Anne; Lukens, Wayne; Delbecq, Francoise; Sautet, Philippe et al.
Object Type:
Article
System:
The UNT Digital Library
Optimization of the cooling profile to achieve crack-free Yb:S-FAP crystals
Yb:S-FAP [Yb{sup 3+}:Sr{sub 5}(PO{sub 4}){sub 3}F] crystals are an important gain medium for diode-pumped laser applications. Growth of 7.0 cm diameter Yb:S-FAP crystals utilizing the Czochralski (CZ) method from SrF{sub 2}-rich melts often encounter cracks during the post growth cool down stage. To suppress cracking during cool down, a numerical simulation of the growth system was used to understand the correlation between the furnace power during cool down and the radial temperature differences within the crystal. The critical radial temperature difference, above which the crystal cracks, has been determined by benchmarking the simulation results against experimental observations. Based on this comparison, an optimal three-stage ramp-down profile was implemented and produced high quality, crack-free Yb:S-FAP crystals.
Date:
August 20, 2007
Creator:
Fang, H; Qiu, S; Kheng, L; Schaffers, K; Tassano, J; Caird, J et al.
Object Type:
Article
System:
The UNT Digital Library
Benchmark Measurements of the Ionization Balance of Non-LTE Gold
The authors present a series of benchmark measurements of the ionization balance of well characterized gold plasmas with and without external radiation fields at electron densities near 10{sup 21} cm{sup -3} and various electron temperatures spanning the range 0.8 to 2.4 keV. They have analyzed time- and space-resolved M-shell gold emission spectra using a sophisticated collisional-radiative model with hybrid level structure, finding average ion changes <Z> ranging from 42 to 50. At the lower temperatures, the spectra exhibit significant sensitivity to external radiation fields and include emission features from complex N-shell ions not previously studied at these densities. The measured spectra and inferred <Z> provide a stringent test for non-local thermodynamic equilibrium (non-LTE) models of complex high-Z ions.
Date:
April 20, 2007
Creator:
Heeter, R. F.; Hansen, S. B.; Fournier, K. B.; Foord, M. E.; Froula, D. H.; Mackinnon, A. J. et al.
Object Type:
Article
System:
The UNT Digital Library
MMA, A Computer Code for Multi-Model Analysis
This report documents the Multi-Model Analysis (MMA) computer code. MMA can be used to evaluate results from alternative models of a single system using the same set of observations for all models. As long as the observations, the observation weighting, and system being represented are the same, the models can differ in nearly any way imaginable. For example, they may include different processes, different simulation software, different temporal definitions (for example, steady-state and transient models could be considered), and so on. The multiple models need to be calibrated by nonlinear regression. Calibration of the individual models needs to be completed before application of MMA. MMA can be used to rank models and calculate posterior model probabilities. These can be used to (1) determine the relative importance of the characteristics embodied in the alternative models, (2) calculate model-averaged parameter estimates and predictions, and (3) quantify the uncertainty of parameter estimates and predictions in a way that integrates the variations represented by the alternative models. There is a lack of consensus on what model analysis methods are best, so MMA provides four default methods. Two are based on Kullback-Leibler information, and use the AIC (Akaike Information Criterion) or AICc (second-order-bias-corrected AIC) model …
Date:
August 20, 2007
Creator:
Hill, Eileen P. Poeter and Mary C.
Object Type:
Report
System:
The UNT Digital Library
Extracellular Proteins Limit the Dispersal of Biogenic Nanoparticles
None
Date:
February 20, 2007
Creator:
Moreau, J W; Weber, P K; Martin, M C; Gilbert, B; Hutcheon, I D & Banfield, J F
Object Type:
Article
System:
The UNT Digital Library
Potential Alternative Energy Technologies on the Outer Continental Shelf.
This technical memorandum (TM) describes the technology requirements for three alternative energy technologies for which pilot and/or commercial projects on the U.S. Outer Continental Shelf (OCS) are likely to be proposed within the next five to seven years. For each of the alternative technologies--wind, wave, and ocean current--the TM first presents an overview. After each technology-specific overview, it describes the technology requirements for four development phases: site monitoring and testing, construction, operation, and decommissioning. For each phase, the report covers the following topics (where data are available): facility description, electricity generated, ocean area (surface and bottom) occupied, resource requirements, emissions and noise sources, hazardous materials stored or used, transportation requirements, and accident potential. Where appropriate, the TM distinguishes between pilot-scale (or demonstration-scale) facilities and commercial-scale facilities.
Date:
April 20, 2007
Creator:
Elcock, D. & Assessment, Environmental
Object Type:
Report
System:
The UNT Digital Library
Molecular Modeling of Solid Fluid Phase Behavior
This report gives a summary of the achievements under DOE contract No. DOE/ER/14150 during the period September 1, 1990 to December 31, 2007. This project was concerned with the molecular modeling of solid-fluid equilibrium. The focus was on understanding how solid-fluid and solid-solid phase behavior are related to molecular structure, and the research program made a seminal contribution in this area. The project led to 34 journal articles, including a comprehensive review article published in Advances in Chemical Physics. The DOE funding supported the work of 5 Ph.D. students, 2 M.S. students and 5 postdoctoral researchers.
Date:
December 20, 2007
Creator:
Monson, Peter A.
Object Type:
Report
System:
The UNT Digital Library
Modeling Leaking Gas Plume Migration
In this study, we obtain simple estimates of 1-D plume propagation velocity taking into account the density and viscosity contrast between CO{sub 2} and brine. Application of the Buckley-Leverett model to describe buoyancy-driven countercurrent flow of two immiscible phases leads to a transparent theory predicting the evolution of the plume. We obtain that the plume does not migrate upward like a gas bubble in bulk water. Rather, it stretches upward until it reaches a seal or until the fluids become immobile. A simple formula requiring no complex numerical calculations describes the velocity of plume propagation. This solution is a simplification of a more comprehensive theory of countercurrent plume migration that does not lend itself to a simple analytical solution (Silin et al., 2006). The range of applicability of the simplified solution is assessed and provided. This work is motivated by the growing interest in injecting carbon dioxide into deep geological formations as a means of avoiding its atmospheric emissions and consequent global warming. One of the potential problems associated with the geologic method of sequestration is leakage of CO{sub 2} from the underground storage reservoir into sources of drinking water. Ideally, the injected green-house gases will stay in the injection …
Date:
August 20, 2007
Creator:
Silin, Dmitriy; Patzek, Tad & Benson, Sally M.
Object Type:
Article
System:
The UNT Digital Library
Mechanical Design and Analysis of a 200 MHz, Bolt-together RFQ forthe Accelerator Driven Neutron Source
A high-yield neutron source to screen sea-land cargocontainers for shielded Special Nuclear Materials (SNM) has been designedat LBNL [1,2]. The Accelerator-Driven Neutron Source (ADNS) uses theD(d,n)3He reaction to create a forward directed neutron beam. Keycomponents are a high-current radio-frequency quadrupole (RFQ)accelerator and a high-power target capable of producing a neutron fluxof>107 n/(cm2 cdot s) at a distance of 2.5 m. The mechanical designand analysis of the four-module, bolt-together RFQ will be presentedhere. Operating at 200 MHz, the 5.1 m long RFQ will accelerate a 40 mAdeuteron beam to 6 MeV. At a 5 percent duty factor, the time-average d+beam current on target is 1.5 mA. Each of the 1.27 m long RFQ moduleswill consist of four solid OFHC copper vanes. A specially designed 3-DO-ring will provide vacuum sealing between both the vanes and themodules. RF connections are made with canted coil spring contacts. Aseries of 60 water-cooled pi-mode rods provides quadrupole modestabilization. A set of 80 evenly spaced fixed slug tuners is used forfinal frequency adjustment and local field perturbationcorrection.
Date:
June 20, 2007
Creator:
Virostek, Steve; Hoff, Matt; Li, Derun; Staples, John & Wells,Russell
Object Type:
Article
System:
The UNT Digital Library
Accuracy tests of the tessellated SLBM model
We have compared the Seismic Location Base Model (SLBM) tessellated model (version 2.0 Beta, posted July 3, 2007) with the GNEMRE Unified Model. The comparison is done on a layer/depth-by-layer/depth and layer/velocity-by-layer/velocity comparison. The SLBM earth model is defined on a tessellation that spans the globe at a constant resolution of about 1 degree (Ballard, 2007). For the tests, we used the earth model in file ''unified{_}iasp.grid''. This model contains the top 8 layers of the Unified Model (UM) embedded in a global IASP91 grid. Our test queried the same set of nodes included in the UM model file. To query the model stored in memory, we used some of the functionality built into the SLBMInterface object. We used the method get InterpolatedPoint() to return desired values for each layer at user-specified points. The values returned include: depth to the top of each layer, layer velocity, layer thickness and (for the upper-mantle layer) velocity gradient. The SLBM earth model has an extra middle crust layer whose values are used when Pg/Lg phases are being calculated. This extra layer was not accessed by our tests. Figures 1 to 8 compare the layer depths, P velocities and P gradients in the UM …
Date:
July 20, 2007
Creator:
Ramirez, A L & Myers, S C
Object Type:
Report
System:
The UNT Digital Library
Polaron Coherence Condensation As the Mechanism for Colossal Magnetoresistance in Layered Manganites
Angle-resolved photoemission spectroscopy data for the bilayer manganite La{sub 1.2}Sr{sub 1.8}Mn{sub 2}O{sub 7} show that, upon lowering the temperature below the Curie point, a coherent polaronic metallic groundstate emerges very rapidly with well defined quasiparticles which track remarkably well the electrical conductivity, consistent with macroscopic transport properties. Our data suggest that the mechanism leading to the insulator-to-metal transition in La{sub 1.2}Sr{sub 1.8}Mn{sub 2}O{sub 7} can be regarded as a polaron coherence condensation process acting in concert with the Double Exchange interaction.
Date:
November 20, 2007
Creator:
Mannella, N.; Yang, W. L.; Tanaka, K.; Zhou, X. J.; Zheng, H.; Mitchell, J. F. et al.
Object Type:
Report
System:
The UNT Digital Library
Fast Extraction Kicker for the Accelerator Test Facility
We present the results of a study for the design of a fastextraction kicker to be installed in the Accelerator Test Facility ringat KEK. This activity is carried on in the framework of the ATF2 project,which will be built on the KEK Tsukuba campus as an extension of theexisting ATF, taking advantage of the world s smallest normalizedemittance achieved there. ATF2's primary goal is to operate as a testfacility and establish the hardware and beam handling technologiesenvisaged for the International Linear Collider. In particular, the fastextraction kicker object of the present paper is an important componentof the ILC damping rings, since its rise and fall time define the minimumdistance between bunches and ultimately the damping rings length itself.Building on the initial results presented at EPAC '06, we report on thepresent status of the kicker design and define the minimumcharacteristics for pulsers and other subsystems. In addition to theoriginal scheme with multiple stripline modules producing a totaldeflection of 5 mrad, we also investigated a scheme with a single kickermodule for a reduced deflection of 1 mrad placed inside a closed orbitbump, which takes the electron closer to the extractionseptum.
Date:
June 20, 2007
Creator:
De Santis, Stefano; Urakawa, Junji & Naito, Takashi
Object Type:
Article
System:
The UNT Digital Library
STATS SRS v11.0
The objective of this project is the delivery of an application that will provide a unified, web-based system for collecting, verifying and analyzing the achievements for Laboratory employees. The application will enable individual Directorates to manage and report achievement record data for their employees using an LLNL standard web browser. In addition, cross directorate data reporting and analysis will be available for such organizations as LSTO and programmatic directorates. This system is intended to store reference data and metadata for employee achievements. Abstracts and entire publications will not be stored in this system.Directorates are expected to use this system at all levels of management in preparing for Annual Self-Assessments, peer reviews, LDRD reviews, work force reviews, performance appraisals, and requests from sponsors. This document represents the primary deliverable for the Requirements Definition stage of system development. As part of a successful Requirements Definition, this document provides the development staff, the project sponsor, and the user community with a clear understanding of the product's operational, data, and other requirements. With this understanding, the development staff will take the opportunity to refine estimates regarding the cost, schedule, and deliverables reflected in it.
Date:
June 20, 2007
Creator:
Piscotty, M A & Nazario, O L
Object Type:
Report
System:
The UNT Digital Library
Measurement of Sin(2beta) in Tree Dominated B0 Decays And Ambiguity Removal
The most recent results from the B-factories on the time-dependent CP asymmetries measured in B{sup 0}-decays mediated by b {yields} c{bar c}s quark-transitions are reviewed. The Standard Model interpretation of the results in terms of the parameter sin 2{beta} leads to a four-fold ambiguity on the unitarity triangle {beta} which can be reduced to a two-fold ambiguity by measuring the sign of the parameter cos 2{beta}. The results on cos2{beta} obtained so far are reviewed.
Date:
November 20, 2007
Creator:
Lacker, H.
Object Type:
Article
System:
The UNT Digital Library
Molecular beam epitaxy of InN dots on nitrided sapphire
A series of self-assembled InN dots are grown by radio frequency (RF) plasma-assisted molecular beam epitaxy (MBE) directly on nitrided sapphire. Initial nitridation of the sapphire substrates at 900 C results in the formation of a rough AlN surface layer, which acts as a very thin buffer layer and facilitates the nucleation of the InN dots according to the Stranski-Krastanow growth mode, with a wetting layer of {approx}0.9 nm. Atomic force microscopy (AFM) reveals that well-confined InN nanoislands with the greatest height/width at half-height ratio of 0.64 can be grown at 460 C. Lower substrate temperatures result in a reduced aspect ratio due to a lower diffusion rate of the In adatoms, whereas the thermal decomposition of InN truncates the growth at T>500 C. The densities of separated dots vary between 1.0 x 10{sup 10} cm{sup -2} and 2.5 x 10{sup 10} cm{sup -2} depending on the growth time. Optical response of the InN dots under laser excitation is studied with apertureless near-field scanning optical microscopy and photoluminescence spectroscopy, although no photoluminescence is observed from these samples. In view of the desirable implementation of InN nanostructures into photonic devices, the results indicate that nitrided sapphire is a suitable substrate for …
Date:
April 20, 2007
Creator:
Romanyuk, Yaroslav E.; Dengel, Radu-Gabriel; Stebounova, LarissaV. & Leone, Stephen R.
Object Type:
Article
System:
The UNT Digital Library
SOEC efficiency and cost improvement Part 1 and 2.
Part I: Electrochemical and X-ray Characterization of Solid-Oxide Electrolysis Cell Oxygen Electrodes on Electrolyte Substrates--The governing reaction mechanisms, and the electrode and electrolyte material compositions and structures, that controls the efficiency and durability of the solid oxide electrolysis cells (SOEC) need to be identified and well-understood for a significant improvement in nuclear hydrogen production using high temperature steam electrolysis. ANL conducted experimental analysis of SOEC electrolyte and electrodes to progress in this objective. Our study on the oxygen electrode focused on specifically the effect of electrode crystal structure on its electrochemical performance, and the evolution of the electronic and structural properties of the electrodes while under electrochemical conditions and high temperature. We found through electrochemical impedance spectroscopy experiments that, while different crystal orientations in La{sub 0.8}Sr{sub 0.2}MnO{sub 3+d} (LSM) show different initial performance and different electrochemical activation under SOEC conditions, a good mixed ionic electronic conductor La{sub 0.8}Sr{sub 0.2}CoO{sub 3+d} (LSC) does not seem to exhibit similar variations. Our in-situ x-ray and electrochemical measurements at the Advanced Photon Source of ANL have identified the chemical states of the A-site elements of the doped lanthanum manganite electrodes. We found that the changes in the concentration and in the electronic state of …
Date:
June 20, 2007
Creator:
Yildiz, B.; Chang, K.-C.; Meyers, D. J.; You, H.; Carter, J. D.; Elam, J. W. et al.
Object Type:
Report
System:
The UNT Digital Library
K-corrections and spectral templates of Type Ia supernovae
With the advent of large dedicated Type Ia supernova (SN Ia) surveys, K-corrections of SNe Ia and their uncertainties have become especially important in the determination of cosmological parameters. While K-corrections are largely driven by SN Ia broadband colors, it is shown here that the diversity in spectral features of SNe Ia can also be important. For an individual observation, the statistical errors from the inhomogeneity in spectral features range from 0.01 (where the observed and rest-frame filters are aligned) to 0.04 (where the observed and rest-frame filters are misaligned). To minimize the systematic errors caused by an assumed SN Ia spectral energy distribution (SED), we outline a prescription for deriving a mean spectral template time series that incorporates a large and heterogeneous sample of observed spectra. We then remove the effects of broadband colors and measure the remaining uncertainties in the K-corrections associated with the diversity in spectral features. Finally, we present a template spectroscopic sequence near maximum light for further improvement on the K-correction estimate. A library of ~;;600 observed spectra of ~;;100 SNe Ia from heterogeneous sources is used for the analysis.
Date:
March 20, 2007
Creator:
Nugent, Peter E.; Hsiao, E. Y.; Conley, A.; Howell, D. A.; Sullivan, M.; Pritchet, C. J. et al.
Object Type:
Article
System:
The UNT Digital Library
Greensheet (Houston, Tex.), Vol. 38, No. 548, Ed. 1 Thursday, December 20, 2007
Free weekly newspaper that includes business and classified advertising.
Date:
December 20, 2007
Creator:
unknown
Object Type:
Newspaper
System:
The Portal to Texas History
Greensheet (Houston, Tex.), Vol. 38, No. 393, Ed. 1 Thursday, September 20, 2007
Free weekly newspaper that includes business and classified advertising.
Date:
September 20, 2007
Creator:
unknown
Object Type:
Newspaper
System:
The Portal to Texas History
Greensheet (Houston, Tex.), Vol. 38, No. 549, Ed. 1 Thursday, December 20, 2007
Free weekly newspaper that includes business and classified advertising.
Date:
December 20, 2007
Creator:
unknown
Object Type:
Newspaper
System:
The Portal to Texas History
Greensheet (Houston, Tex.), Vol. 38, No. 25, Ed. 1 Tuesday, February 20, 2007
Free weekly newspaper that includes business and classified advertising.
Date:
February 20, 2007
Creator:
unknown
Object Type:
Newspaper
System:
The Portal to Texas History
Greensheet (Houston, Tex.), Vol. 38, No. 73, Ed. 1 Tuesday, March 20, 2007
Free weekly newspaper that includes business and classified advertising.
Date:
March 20, 2007
Creator:
unknown
Object Type:
Newspaper
System:
The Portal to Texas History