Anaerobic Fe(III) reduction by Shewanella putrefaciens: Analysis of the electron transport chain (open access)

Anaerobic Fe(III) reduction by Shewanella putrefaciens: Analysis of the electron transport chain

The goals of the project were to isolate mutants that are deficient in metal reduction, identify components of the electron transport chain that are involved in this process, and purify some of these proteins for biochemical analyses. In the 3-year period since the start of the project, we have accomplished many of these goals. We have isolated several new S. oneidensis mutants that are deficient in metal reduction, and have initiated the development of vectors for the overexpression of cytochromes and other proteins in S. oneidensis. We have also overexpressed CymA, one of the c cytochromes that are involved in metal reduction.
Date: January 20, 2004
Creator: Saffarini, Daad
Object Type: Report
System: The UNT Digital Library
Closed orbit response to quadrupole strength variation (open access)

Closed orbit response to quadrupole strength variation

We derive two formulae relating the variation in closed orbit in a storage ring to variations in quadrupole strength, neglecting nonlinear and dispersive effects. These formulae correct results previously reported [1,2,3]. We compare the results of the formulae applied to the ATF with simulations using MAD, and consider their application to beam-based alignment.
Date: January 20, 2004
Creator: Wolski, Andrzej & Zimmermann, Frank
Object Type: Report
System: The UNT Digital Library
Failure of Vapor Overheads Discharge Line for a Radioactive Waste Evaporator (open access)

Failure of Vapor Overheads Discharge Line for a Radioactive Waste Evaporator

A 2-inch schedule 40 steel core pipe in an evaporator overheads discharge line broke at several locations downstream from a section of the line where it bridges a road. Fish mouth openings that developed along the pipe seams were initiated at lack of fusion defects in the pipe welds. A vacuum created in the piping upstream of the breaks prevented full drainage of the water upon shut down of the pump. Freezing of water in the pipe (the line was not heat traced) and water hammer effects occurring with pump restart could each contribute to the extensive deformation and tearing observed at the breaks. Both the weld flaws and the over pressure contributed to the outcome. All pipe was replaced and a vacuum break was installed to eliminate the problem.
Date: January 20, 2004
Creator: Jenkins, C.F.
Object Type: Article
System: The UNT Digital Library
A Fundamental Study of Laser-Induced Breakdown Spectroscopy Using Fiber Optics for Remote Measurements Of Trace Metals (open access)

A Fundamental Study of Laser-Induced Breakdown Spectroscopy Using Fiber Optics for Remote Measurements Of Trace Metals

Develop a fiber-optic imaging probe for microanalysis of solid samples; Design a time-resolved plasma imaging system to measure the development of the LIBS signal; Setup a laboratory system capable of timing two lasers independently, for optimizing and characterizing dual-pulse LIBS; Compare the development of laser-induced plasmas generated with a single laser pulse to the development of laser-induced plasmas generated with a pre-ablation spark prior to sample ablation; Examine the effect of sample matrix on the LIBS signals of elements in different sample matrices; Investigate the effect of excitation wavelength of the ablation beam in pre-ablation spark dual-pulse LIBS experiments; Determine the effect of the physical properties of the sample on the mass of materials ablated.
Date: January 20, 2004
Creator: Goode, Scott & Angel, S. Michael
Object Type: Report
System: The UNT Digital Library
HARNESS: Heterogeneous Adaptable Reconfigurable Networked Systems. Final Progress Report (open access)

HARNESS: Heterogeneous Adaptable Reconfigurable Networked Systems. Final Progress Report

HARNESS was proposed as a system that combined the best of emerging technologies found in current distributed computing research and commercial products into a very flexible, dynamically adaptable framework that could be used by applications to allow them to evolve and better handle their execution environment. The HARNESS system was designed using the considerable experience from previous projects such as PVM, MPI, IceT and Cumulvs. As such, the system was designed to avoid any of the common problems found with using these current systems, such as no single point of failure, ability to survive machine, node and software failures. Additional features included improved intercomponent connectivity, with full support for dynamic down loading of addition components at run-time thus reducing the stress on application developers to build in all the libraries they need in advance.
Date: January 20, 2004
Creator: Fagg, G. E.
Object Type: Report
System: The UNT Digital Library
Identifying performance bottlenecks on modern microarchitectures using an adaptable probe (open access)

Identifying performance bottlenecks on modern microarchitectures using an adaptable probe

The gap between peak and delivered performance for scientific applications running on microprocessor-based systems has grown considerably in recent years. The inability to achieve the desired performance even on a single processor is often attributed to an inadequate memory system, but without identification or quantification of a specific bottleneck. In this work, we use an adaptable synthetic benchmark to isolate application characteristics that cause a significant drop in performance, giving application programmers and architects information about possible optimizations. Our adaptable probe, called sqmat, uses only four parameters to capture key characteristics of scientific workloads: working-set size, computational intensity, indirection, and irregularity. This paper describes the implementation of sqmat and uses its tunable parameters to evaluate four leading 64-bit microprocessors that are popular building blocks for current high performance systems: Intel Itanium2, AMD Opteron, IBM Power3, and IBM Power4.
Date: January 20, 2004
Creator: Griem, Gorden; Oliker, Leonid; Shalf, John & Yelick, Katherine
Object Type: Article
System: The UNT Digital Library
Life-Cycle Cost Analysis of Energy Efficiency Design Options for Residential Furnaces and Boilers (open access)

Life-Cycle Cost Analysis of Energy Efficiency Design Options for Residential Furnaces and Boilers

In 2001, the U.S. Department of Energy (DOE) initiated a rulemaking process to consider whether to amend the existing energy efficiency standards for furnaces and boilers. A key factor in DOE's consideration of new standards is the economic impacts on consumers of possible revisions to energy-efficiency standards. Determining cost-effectiveness requires an appropriate comparison of the additional first cost of energy efficiency design options with the savings in operating costs. DOE's preferred approach involves comparing the total life-cycle cost (LCC) of owning and operating a more efficient appliance with the LCC for a baseline design. This study describes the method used to conduct the LCC analysis and presents the estimated change in LCC associated with more energy-efficient equipment. The results indicate that efficiency improvement relative to the baseline design can reduce the LCC in each of the product classes considered.
Date: January 20, 2004
Creator: Lutz, James; Lekov, Alex; Whitehead, Camilla Dunham; Chan, Peter; Meyers,Steve & McMahon, James
Object Type: Report
System: The UNT Digital Library
Lipid Membrane Composition Analyzed by Multi-isotope Imaging Mass Spectrometry (open access)

Lipid Membrane Composition Analyzed by Multi-isotope Imaging Mass Spectrometry

The lateral organization of lipids and membrane-associated proteins in biological membranes is often detected by fluorescence microscopy. Although extremely sensitive, fluorescent labels, particularly those attached to lipid molecules, may alter their physical properties.
Date: January 20, 2004
Creator: Hutcheon, I D; Weber, P K; Marxer, C G; Park, E S & Boxer, S G
Object Type: Article
System: The UNT Digital Library
The Numerical Electromagnetics Code (NEC) - A Brief History (open access)

The Numerical Electromagnetics Code (NEC) - A Brief History

The Numerical Electromagnetics Code, NEC as it is commonly known, continues to be one of the more widely used antenna modeling codes in existence. With several versions in use that reflect different levels of capability and availability, there are now 450 copies of NEC4 and 250 copies of NEC3 that have been distributed by Lawrence Livermore National Laboratory to a limited class of qualified recipients, and several hundred copies of NEC2 that had a recorded distribution by LLNL. These numbers do not account for numerous copies (perhaps 1000s) that were acquired through other means capitalizing on the open source code, the absence of distribution controls prior to NEC3 and the availability of versions on the Internet. In this paper we briefly review the history of the code that is concisely displayed in Figure 1. We will show how it capitalized on the research of prominent contributors in the early days of computational electromagnetics, how a combination of events led to the tri-service-supported code development program that ultimately led to NEC and how it evolved to the present day product. The authors apologize that space limitations do not allow us to provide a list of references or to acknowledge the numerous …
Date: January 20, 2004
Creator: Burke, G J; Miller, E K & Poggio, A J
Object Type: Article
System: The UNT Digital Library
Pilot-Scale Testing of a Rotary Microfilter with Irradiated Filter Disks and Simulated SRS Waste (open access)

Pilot-Scale Testing of a Rotary Microfilter with Irradiated Filter Disks and Simulated SRS Waste

The processing rate of the Actinide Removal Project (ARP) is limited by the flow rate of the solid-liquid separation process. If the Department of Energy, DOE, could identify and develop a solid- liquid separation technology with a higher filter flux, they could increase the throughput of the Actinide Removal Project and complete treating that fraction of the waste stream in a shorter time, with a significant reduction in life-cycle cost. Savannah River Technology Center personnel identified the rotary microfilter as a technology that could significantly increase filter flux, with improvements of as much as 10X over the 0.5 micron crossflow filter and 5X over the 0.1 micron crossflow filter. The Savannah River Technology Center received funding from the DOE-HQ, Office of Cleanup Technologies, to evaluate and develop the rotary microfilter for radioactive service at the Savannah River Site. The authors performed pilot-scale simulant filtration tests with irradiated filter disks. They employed three types of filter disks for the tests (0.5 m stainless steel, 0.1 m stainless steel, and 0.1 m ceramic/stainless steel). They analyzed the filter's structural material, Ryton(R) for hardness, and irradiated the entire disk with an estimated 2.5-5 year (83-165 MRad) radiation dose. They measured the hardness of …
Date: January 20, 2004
Creator: POIRIER, MICHAELR.
Object Type: Report
System: The UNT Digital Library
Position Estimation of Transceivers in Communication Networks (open access)

Position Estimation of Transceivers in Communication Networks

With rapid developments in wireless sensor networks, there is a growing need for transceiver position estimation independent of GPS, which may not be available in indoor networks. Our approach is to use range estimates from time-of-flight (TOF) measurements, a technique well suited to large bandwidth physical links, such as in ultra-wideband (UWB) systems. In our UWB systems, pulse duration less than 200 psecs can easily be resolved to less than a foot. Assuming an encoded UWB physical layer, we first test positioning accuracy using simulations. We are interested in sensitivity to range errors and the required number of ranging nodes, and we show that in a high-precision environment, such as UWB, the optimal number of transmitters is four. Four transmitters with {+-}20ft. range error can locate a receiver to within one or two feet. We then implement these algorithms on an 802.11 wireless network and demonstrate the ability to locate a network access point to approximately 20 feet.
Date: January 20, 2004
Creator: Dowla, F. & Kent, C.
Object Type: Article
System: The UNT Digital Library
Radiological Design Summary Report for TRU Vent and Purge Process (open access)

Radiological Design Summary Report for TRU Vent and Purge Process

This report contains top-level requirements for the various areas of radiological protection for workers. Detailed quotations of the requirements for applicable regulatory documents can be found in the accompanying Implementation Guide. For the purposes of demonstrating compliance with these requirements, per Engineering Standard 01064, shall consider / shall evaluate indicates that the designer must examine the requirement for the design and either incorporate or provide a technical justification as to why the requirement is not incorporated. The Transuranic Vent and Purge process is not a project, but is considered a process change. This process has been performed successfully by Solid Waste on lower activity TRU drums. This summary report applies a graded approach and describes how the Transuranic Vent and Purge process meets each of the applicable radiological design criteria and requirements specified in Manual WSRC-TM-95-1, Engineering Standard Number 01064.
Date: January 20, 2004
Creator: Taus, L.B.
Object Type: Report
System: The UNT Digital Library
Remote Chemical Sensing Using Quantum Cascade Lasers (open access)

Remote Chemical Sensing Using Quantum Cascade Lasers

Research done by the IR sensors team at PNNL is focused on developing advanced spectroscopic methods for detecting signatures of nuclear, chemical, biological and explosives weapons or weapons production. The sensors we develop fall into two categories: remote sensors that can be operated at distances ranging from 150 m to 10 km, and point sensors that are used for in-situ inspection and detection. FY03 has seen an explosion in FM DIAL progress with the net result being solid confirmation that FM DIAL is a technique capable of remote chemical monitoring in a wide variety of venues. For example, FM DIAL was used to detect a small plume of hydrogen sulfide, a candidate CW agent, released in the desert environment of the Hanford 200 Area site. These experiments were conducted over a range of physical conditions including outside temperatures ranging from 70 F to 105 F and turbulence conditions ranging from quiescent to chaotic. We are now rapidly developing the information needed to design prototype FM DIAL systems that are optimized for specific applications that include scenarios such as fixed position stand-off detection and mobile UAV mounted remote monitoring. Just as an example, in FY04 we will use FM DIAL to …
Date: January 20, 2004
Creator: Harper, Warren W.; Strasburg, Jana D.; Aker, Pam M. & Schultz, John F.
Object Type: Report
System: The UNT Digital Library
Stability of Stationary Solutions of the Multifrequency Radiation Diffusion Equations (open access)

Stability of Stationary Solutions of the Multifrequency Radiation Diffusion Equations

A nondimensional model of the multifrequency radiation diffusion equation is derived. A single material, ideal gas, equation of state is assumed. Opacities are proportional to the inverse of the cube of the frequency. Inclusion of stimulated emission implies a Wien spectrum for the radiation source function. It is shown that the solutions are uniformly bounded in time and that stationary solutions are stable. The spatially independent solutions are asymptotically stable, while the spatially dependent solutions of the linearized equations approach zero.
Date: January 20, 2004
Creator: Hald, O H & Shestakov, A I
Object Type: Article
System: The UNT Digital Library
Synthesis and optical properties of II-O-VI highly mismatched alloys (open access)

Synthesis and optical properties of II-O-VI highly mismatched alloys

We have synthesized ternary and quaternary diluted II-VI oxides using the combination of O ion implantation and pulsed laser melting. CdO{sub x}Te{sub 1-x} thin films with x up to 0.015, and the energy gap reduced by 150 meV were formed by O{sup +}-implantation in CdTe followed by pulsed laser melting. Quaternary Cd{sub 0.6}Mn{sub 0.4}O{sub x}Te{sub 1-x} and Zn{sub 0.88}Mn{sub 0.12}O{sub x}Te{sub 1-x} with mole fraction of incorporated O as high as 0.03 were also formed. The enhanced O incorporation in Mn-containing alloys is believed to be due to the formation of relatively strong Mn-O bonds. Optical transitions associated with the lower (E{sub -}) and upper (E{sub +}) conduction subbands resulting from the anticrossing interaction between the localized O states and the extended conduction states of the host are clearly observed in these quaternary diluted II-VI oxides. These alloys fulfill the criteria for a multiband semiconductor that has been proposed as a material for making high efficiency, single-junction solar cells.
Date: January 20, 2004
Creator: Yu, K. M.; Walukiewicz, W.; Shan, W.; Wu, J.; Beeman, J. W.; Scarpulla, M. A. et al.
Object Type: Article
System: The UNT Digital Library
Tracking the Inside Intruder Using Net Log on Debug Logging in Microsoft Windows Server Operating Systems (open access)

Tracking the Inside Intruder Using Net Log on Debug Logging in Microsoft Windows Server Operating Systems

In today's well-connected environments of the Internet, intranets, and extranets, protecting the Microsoft Windows network can be a daunting task for the security engineer. Intrusion Detection Systems are a must-have for most companies, but few have either the financial resources or the people resources to implement and maintain full-scale intrusion detection systems for their networks and hosts. Many will at least invest in intrusion detection for their Internet presence, but others have not yet stepped up to the plate with regard to internal intrusion detection. Unfortunately, most attacks will come from within. Microsoft Windows server operating systems are widely used across both large and small enterprises. Unfortunately, there is no intrusion detection built-in to the Windows server operating system. The security logs are valuable but can be difficult to manage even in a small to medium sized environment. So the question arises, can one effectively detect and identify an in side intruder using the native tools that come with Microsoft Windows Server operating systems? One such method is to use Net Logon Service debug logging to identify and track malicious user activity. This paper discusses how to use Net Logon debug logging to identify and track malicious user activity both …
Date: January 20, 2004
Creator: Davis, CS
Object Type: Report
System: The UNT Digital Library
Tracking the Inside Intruder Using Net Log on Debug Logging in Microsoft Windows Server Operating Systems (open access)

Tracking the Inside Intruder Using Net Log on Debug Logging in Microsoft Windows Server Operating Systems

In today's well-connected environments of the Internet, intranets, and extranets, protecting the Microsoft Windows network can be a daunting task for the security engineer. Intrusion Detection Systems are a must-have for most companies, but few have either the financial resources or the people resources to implement and maintain full-scale intrusion detection systems for their networks and hosts. Many will at least invest in intrusion detection for their Internet presence, but others have not yet stepped up to the plate with regard to internal intrusion detection. Unfortunately, most attacks will come from within. Microsoft Windows server operating systems are widely used across both large and small enterprises. Unfortunately, there is no intrusion detection built-in to the Windows server operating system. The security logs are valuable but can be difficult to manage even in a small to medium sized environment. So the question arises, can one effectively detect and identify an in side intruder using the native tools that come with Microsoft Windows Server operating systems? One such method is to use Net Logon Service debug logging to identify and track malicious user activity. This paper discusses how to use Net Logon debug logging to identify and track malicious user activity both …
Date: January 20, 2004
Creator: Davis, CS
Object Type: Report
System: The UNT Digital Library
UTSI/CFFF MHD PROGRAM COMPLETION AND RELATED ACTIVITY (open access)

UTSI/CFFF MHD PROGRAM COMPLETION AND RELATED ACTIVITY

The Discharge Monitoring Reports (DMRs) for October, November and December, 2003, were prepared and submitted to the Tennessee Department of Environment and Conservation (TDEC). TVG Environmental, Inc. carried out the scheduled groundwater well sampling on November 17, 2003. The CFFF is currently on a semi-annual testing program required by the Tennessee Department of Environment and Conservation. TVG Environmental conducted this semi-annual sampling event for five groundwater wells adjacent to the CFFF. The semi-annual Groundwater Monitoring Report (dated December 17, 2003) from TVG Environmental was received in late December, 2003. The report was noted to have a couple of typographical errors and therefore, it was returned to TVG for correction. The corrected report will be forwarded to DOE in January 2004, as soon as it is received.
Date: January 20, 2004
Creator: Muehlhauser, Joel W.
Object Type: Report
System: The UNT Digital Library
Yb:S-FAP Lasers (open access)

Yb:S-FAP Lasers

It has recently been reported that several high power, diode-pumped laser systems have been developed based on crystals of Yb:S-FAP [Yb{sup 3+}:Sr{sub 5}(PO{sub 4}){sub 3}F]. The Mercury Laser, at Lawrence Livermore National Laboratory, is the most prominent system using Yb:S-FAP and is currently producing 23J at 5 Hz in a 15 nsec pulse, based on partial activation of the system. In addition, a regenerative amplifier is being developed at Waseda University in Japan and has produced greater than 12 mJ with high beam quality at 50Hz repetition rate. Q-peak has demonstrated 16 mJ of maximum energy/output pulse in a multi-pass, diode side-pumped amplifier and ELSA in France is implementing Yb:S-FAP in a 985 nm pump for an EDFA, producing 250 mW. Growth of high optical quality crystals of Yb:S-FAP is a challenge due to multiple crystalline defects. However, at this time, a growth process has been developed to produce high quality 3.5 cm diameter Yb:S-FAP crystals and a process is under development for producing 6.5 cm diameter crystals.
Date: January 20, 2004
Creator: Schaffers, K I
Object Type: Article
System: The UNT Digital Library
317/319 phytoremediation site monitoring report - 2003 growing season. (open access)

317/319 phytoremediation site monitoring report - 2003 growing season.

In 1999, Argonne National Laboratory-East (ANL-E) designed and installed a series of engineered plantings consisting of a vegetative cover system and approximately 800 hybrid poplars and willows rooting at various predetermined depths. The plants were installed using various methods including Applied Natural Science's TreeWell{reg_sign} system. The goal of the installation was to protect downgradient surface and groundwater by hydraulic control of the contaminated plume by intercepting the contaminated groundwater with the tree roots, removing moisture from the upgradient soil area, reducing water infiltration, preventing soil erosion, degrading and/or transpiring the residual volatile organic compounds (VOCs), and removing tritium from the subsoil and groundwater. This report presents the results of the monitoring activities conducted by Argonne's Energy Systems Division (ES) in the growing season of 2003. ES was tasked with the biomonitoring of the plantation to determine contaminant uptake and groundwater contact. VOCs were found in plant tissue both at the French Drain and the Hydraulic Control locations in varying concentrations, and tritium levels in transpirate was found to continue a trend of higher concentrations compared to the background in the ANL-E area.
Date: February 20, 2004
Creator: Negri, M. C.; Gopalakrishnan, G.; Hamilton, C. & Systems, Energy
Object Type: Report
System: The UNT Digital Library
The BTeV Software Tutorial Suite (open access)

The BTeV Software Tutorial Suite

The BTeV Collaboration is starting to develop its C++ based offline software suite, an integral part of which is a series of tutorials. These tutorials are targeted at a diverse audience, including new graduate students, experienced physicists with little or no C++ experience, those with just enough C++ to be dangerous, and experts who need only an overview of the available tools. The tutorials must both teach C++ in general and the BTeV specific tools in particular. Finally, they must teach physicists how to find and use the detailed documentation. This report will review the status of the BTeV experiment, give an overview of the plans for and the state of the software and will then describe the plans for the tutorial suite.
Date: February 20, 2004
Creator: Kutschke, Robert K.
Object Type: Article
System: The UNT Digital Library
Chandra Low Energy Transmission Grating Spectrum of SS Cygni in Outburst (open access)

Chandra Low Energy Transmission Grating Spectrum of SS Cygni in Outburst

We have fitted the Chandra Low Energy Transmission Grating spectrum of SS Cygni in outburst with a single temperature blackbody suffering the photoelectric opacity of a neutral column density and the scattering opacity of an outflowing wind. We find that this simple model is capable of reproducing the essential features of the observed spectrum with the blackbody temperature T{sub bl} {approx} 250{+-}50 kK, hydrogen column density N{sub H} {approx} 5.0{sup +2.9}{sub -1.5}x10{sup 19} cm{sup -2}, fractional emitting area f {approx} 5.6{sup +60}{sub -4.5} x10{sup -3}, boundary layer luminosity Lbl {approx} 5{sup +18}{sub -3} x10{sup 33} erg s{sup -1}, wind velocity v {approx} 2500 km s{sup -1}, wind mass-loss rate w {approx} 1.1x10{sup 16} g s{sup -1}, and arbitrary values of the wind ionization fractions of 20 ions of O, Ne,Mg, Si, S, and Fe. Given that in outburst the accretion disk luminosity L{sub disk} {approx}1x10{sup 35} erg s{sup -1}, L{sub bl}/L{sub disk} {approx} 0.05{sup +0.18}{sub -0.03}, which can be explained if the white dwarf (or an equatorial belt thereon) is rotating with an angular velocity {Omega}{sub wd} {approx} 0.7{sup +0.1}{sub -0.2}Hz, hence V{sub rot}sini {approx} 2300 km s{sup -1}.
Date: February 20, 2004
Creator: Mauche, C W
Object Type: Article
System: The UNT Digital Library
DHS Workshop -- Homeland Security: New Challenges for Decision Making Under Uncertainty (open access)

DHS Workshop -- Homeland Security: New Challenges for Decision Making Under Uncertainty

A workshop addressing the decision-making challenges confronted by the United States Department of Homeland Security (DHS) in the face of large uncertainties, complex value systems, and multiple stakeholders was held November 13-14, 2003, in Washington, D.C. Forty-six participants drawn from the DHS, other government agencies, universities, national laboratories, and the private sector attended the workshop. The goals were: (1) to develop a common understanding of the range of decisions DHS program elements must make; (2) to review selected examples of decision processes and approaches used by other organizations for similarly complex problems; and (3) to recommend steps DHS can take to ensure high quality decision making. The workshop brought together diverse perspectives on decision making in the context of complex risks. Participants included those who must make decisions affecting homeland security, those who have faced risky decisions in other domains, and those who have developed theoretical and practical approaches to high quality decision-making. The workshop was sponsored by the Science & Technology (S&T) Directorate, but was intended to address issues of concern to the three DHS operating directorates as well as S&T. The purpose of this breadth was to identify areas in which S&T capabilities and resources could be valuable …
Date: February 20, 2004
Creator: Wheeler, R; Edmunds, T & Howarth, S
Object Type: Report
System: The UNT Digital Library
Efficient Web Change Monitoring with Page Digest (open access)

Efficient Web Change Monitoring with Page Digest

The Internet and the World Wide Web have enabled a publishing explosion of useful online information, which has produced the unfortunate side effect of information overload: it is increasingly difficult for individuals to keep abreast of fresh information. In this paper we describe an approach for building a system for efficiently monitoring changes to Web documents. This paper has three main contributions. First, we present a coherent framework that captures different characteristics of Web documents. The system uses the Page Digest encoding to provide a comprehensive monitoring system for content, structure, and other interesting properties of Web documents. Second, the Page Digest encoding enables improved performance for individual page monitors through mechanisms such as short-circuit evaluation, linear time algorithms for document and structure similarity, and data size reduction. Finally, we develop a collection of sentinel grouping techniques based on the Page Digest encoding to reduce redundant processing in large-scale monitoring systems by grouping similar monitoring requests together. We examine how effective these techniques are over a wide range of parameters and have seen an order of magnitude speed up over existing Web-based information monitoring systems.
Date: February 20, 2004
Creator: Buttler, David J.; Rocco, Daniel & Liu, Ling
Object Type: Article
System: The UNT Digital Library