Tracking topic birth and death in LDA. (open access)

Tracking topic birth and death in LDA.

Most topic modeling algorithms that address the evolution of documents over time use the same number of topics at all times. This obscures the common occurrence in the data where new subjects arise and old ones diminish or disappear entirely. We propose an algorithm to model the birth and death of topics within an LDA-like framework. The user selects an initial number of topics, after which new topics are created and retired without further supervision. Our approach also accommodates many of the acceleration and parallelization schemes developed in recent years for standard LDA. In recent years, topic modeling algorithms such as latent semantic analysis (LSA)[17], latent Dirichlet allocation (LDA)[10] and their descendants have offered a powerful way to explore and interrogate corpora far too large for any human to grasp without assistance. Using such algorithms we are able to search for similar documents, model and track the volume of topics over time, search for correlated topics or model them with a hierarchy. Most of these algorithms are intended for use with static corpora where the number of documents and the size of the vocabulary are known in advance. Moreover, almost all current topic modeling algorithms fix the number of topics …
Date: September 1, 2011
Creator: Wilson, Andrew T. & Robinson, David Gerald
Object Type: Report
System: The UNT Digital Library
Robust automated knowledge capture. (open access)

Robust automated knowledge capture.

This report summarizes research conducted through the Sandia National Laboratories Robust Automated Knowledge Capture Laboratory Directed Research and Development project. The objective of this project was to advance scientific understanding of the influence of individual cognitive attributes on decision making. The project has developed a quantitative model known as RumRunner that has proven effective in predicting the propensity of an individual to shift strategies on the basis of task and experience related parameters. Three separate studies are described which have validated the basic RumRunner model. This work provides a basis for better understanding human decision making in high consequent national security applications, and in particular, the individual characteristics that underlie adaptive thinking.
Date: October 1, 2011
Creator: Stevens-Adams, Susan Marie; Abbott, Robert G.; Forsythe, James Chris; Trumbo, Michael Christopher Stefan; Haass, Michael Joseph & Hendrickson, Stacey M. Langfitt
Object Type: Report
System: The UNT Digital Library
LaserFest Celebration (open access)

LaserFest Celebration

LaserFest was the yearlong celebration, during 2010, of the 50th anniversary of the demonstration of the first working laser. The goals of LaserFest were: to highlight the impact of the laser in its manifold commercial, industrial and medical applications, and as a tool for ongoing scientific research; to use the laser as one example that illustrates, more generally, the route from scientific innovation to technological application; to use the laser as a vehicle for outreach, to stimulate interest among students and the public in aspects of physical science; to recognize and honor the pioneers who developed the laser and its many applications; to increase awareness among policymakers of the importance of R&D funding as evidenced by such technology as lasers. One way in which LaserFest sought to meet its goals was to encourage relevant activities at a local level all across the country -- and also abroad -- that would be identified with the larger purposes of the celebration and would carry the LaserFest name. Organizers were encouraged to record and advertise these events through a continually updated web-based calendar. Four projects were explicitly detailed in the proposals: 1) LaserFest on the Road; 2) Videos; 3) Educational material; and 4) …
Date: August 25, 2011
Creator: Chodos, Alan & Rogan, Elizabeth A.
Object Type: Text
System: The UNT Digital Library
Photocathode Optimization for a Dynamic Transmission Electron Microscope: Final Report (open access)

Photocathode Optimization for a Dynamic Transmission Electron Microscope: Final Report

The Dynamic Transmission Electron Microscope (DTEM) team at Harvey Mudd College has been sponsored by LLNL to design and build a test setup for optimizing the performance of the DTEM's electron source. Unlike a traditional TEM, the DTEM achieves much faster exposure times by using photoemission from a photocathode to produce electrons for imaging. The DTEM team's work is motivated by the need to improve the coherence and current density of the electron cloud produced by the electron gun in order to increase the image resolution and contrast achievable by DTEM. The photoemission test setup is nearly complete and the team will soon complete baseline tests of electron gun performance. The photoemission laser and high voltage power supply have been repaired; the optics path for relaying the laser to the photocathode has been finalized, assembled, and aligned; the internal setup of the vacuum chamber has been finalized and mostly implemented; and system control, synchronization, and data acquisition has been implemented in LabVIEW. Immediate future work includes determining a consistent alignment procedure to place the laser waist on the photocathode, and taking baseline performance measurements of the tantalum photocathode. Future research will examine the performance of the electron gun as a …
Date: August 4, 2011
Creator: Ellis, Perry; Flom, Zeke; Heinselman, Karen; Nguyen, Tim; Tung, Spencer; Haskell, Richard et al.
Object Type: Report
System: The UNT Digital Library
Second Line of Defense Help Desk: Electronic Maintenance Reports - Local Maintenance Provider User Guide Rev. 1 (open access)

Second Line of Defense Help Desk: Electronic Maintenance Reports - Local Maintenance Provider User Guide Rev. 1

The Electronic Maintenance Report forms present a uniform dataset for analysis of Sustainability metrics. These forms collect readily minable data while allowing the attachment of site-specific checklists or other supporting files for review by the Sustainability Manager and Program Management.
Date: December 14, 2011
Creator: Leigh, Richard J.
Object Type: Report
System: The UNT Digital Library
AGN Unification at z ~ 1: u - R Colors and Gradients in X-ray AGN Hosts (open access)

AGN Unification at z ~ 1: u - R Colors and Gradients in X-ray AGN Hosts

None
Date: July 11, 2011
Creator: Ammons, S. M.; Rosario, D.; Koo, D.; Dutton, A.; Melbourne, J.; Max, C. et al.
Object Type: Article
System: The UNT Digital Library
Cognitive Foundations for Visual Analytics (open access)

Cognitive Foundations for Visual Analytics

In this report, we provide an overview of scientific/technical literature on information visualization and VA. Topics discussed include an update and overview of the extensive literature search conducted for this study, the nature and purpose of the field, major research thrusts, and scientific foundations. We review methodologies for evaluating and measuring the impact of VA technologies as well as taxonomies that have been proposed for various purposes to support the VA community. A cognitive science perspective underlies each of these discussions.
Date: February 25, 2011
Creator: Greitzer, Frank L.; Noonan, Christine F. & Franklin, Lyndsey
Object Type: Report
System: The UNT Digital Library
DEPOSITION OF NIOBIUM AND OTHER SUPERCONDUCTING MATERIALS WITH HIGH POWER IMPULSE MAGNETRON SPUTTERING: CONCEPT AND FIRST RESULTS (open access)

DEPOSITION OF NIOBIUM AND OTHER SUPERCONDUCTING MATERIALS WITH HIGH POWER IMPULSE MAGNETRON SPUTTERING: CONCEPT AND FIRST RESULTS

Niobium coatings on copper cavities have been considered as a cost-efficient replacement of bulk niobium RF cavities, however, coatings made by magnetron sputtering have not quite lived up to high expectations due to Q-slope and other issues. High power impulse magnetron sputtering (HIPIMS) is a promising emerging coatings technology which combines magnetron sputtering with a pulsed power approach. The magnetron is turned into a metal plasma source by using very high peak power density of ~ 1 kW/cm{sup 2}. In this contribution, the cavity coatings concept with HIPIMS is explained. A system with two cylindrical, movable magnetrons was set up with custom magnetrons small enough to be inserted into 1.3 GHz cavities. Preliminary data on niobium HIPIMS plasma and the resulting coatings are presented. The HIPIMS approach has the potential to be extended to film systems beyond niobium, including other superconducting materials and/or multilayer systems.
Date: July 24, 2011
Creator: High Current Electronics Institute, Tomsk, Russia; Anders, Andre; Mendelsberg, Rueben J.; Lim, Sunnie; Mentink, Matthijs; Slack, Jonathan L. et al.
Object Type: Article
System: The UNT Digital Library
Home Area Networks and the Smart Grid (open access)

Home Area Networks and the Smart Grid

With the wide array of home area network (HAN) options being presented as solutions to smart grid challenges for the home, it is time to compare and contrast their strengths and weaknesses. This white paper examines leading and emerging HAN technologies. The emergence of the smart grid is bringing more networking players into the field. The need for low consistent bandwidth usage differs enough from the traditional information technology world to open the door to new technologies. The predominant players currently consist of a blend of the old and new. Within the wired world Ethernet and HomePlug Green PHY are leading the way with an advantage to HomePlug because it doesn't require installing new wires. In the wireless the realm there are many more competitors but WiFi and ZigBee seem to have the most momentum.
Date: April 1, 2011
Creator: Clements, Samuel L.; Carroll, Thomas E. & Hadley, Mark D.
Object Type: Report
System: The UNT Digital Library
Solar-Assisted Electric Vehicle Charging Station Interim Report (open access)

Solar-Assisted Electric Vehicle Charging Station Interim Report

Oak Ridge National Laboratory (ORNL) has been awarded $6.8 million in the Department of Energy (DOE) American Recovery and Reinvestment Act (ARRA) funds as part of an overall $114.8 million ECOtality grant with matching funds from regional partners to install 125 solar-assisted Electric Vehicle (EV) charging stations across Knoxville, Nashville, Chattanooga, and Memphis. Significant progress has been made toward completing the scope with the installation of 25 solar-assisted charging stations at ORNL; six stations at Electric Power Research Institute (EPRI); and 27 stations at Nissan's Smyrna and Franklin sites, with three more stations under construction at Nissan's new lithium-ion battery plant. Additionally, the procurement process for contracting the installation of 34 stations at Knoxville, the University of Tennessee Knoxville (UTK), and Nashville sites is underway with completion of installation scheduled for early 2012. Progress is also being made on finalizing sites and beginning installations of 30 stations in Nashville, Chattanooga, and Memphis by EPRI and Tennessee Valley Authority (TVA). The solar-assisted EV charging station project has made great strides in fiscal year 2011. A total of 58 solar-assisted EV parking spaces have been commissioned in East and Middle Tennessee, and progress on installing the remaining 67 spaces is well underway. …
Date: September 1, 2011
Creator: Lapsa, Melissa Voss; Durfee, Norman; Maxey, L Curt & Overbey, Randall M
Object Type: Report
System: The UNT Digital Library
Proceedings of RIKEN BNL Research Center Workshop: Initial State Fluctuations and Final-State Particle Correlations (open access)

Proceedings of RIKEN BNL Research Center Workshop: Initial State Fluctuations and Final-State Particle Correlations

N/A
Date: February 2, 2011
Creator: A., Dumitru; Molnar, D. & Wang, F.
Object Type: Report
System: The UNT Digital Library
Optika : a GUI framework for parameterized applications. (open access)

Optika : a GUI framework for parameterized applications.

In the field of scientific computing there are many specialized programs designed for specific applications in areas such as biology, chemistry, and physics. These applications are often very powerful and extraordinarily useful in their respective domains. However, some suffer from a common problem: a non-intuitive, poorly-designed user interface. The purpose of Optika is to address this problem and provide a simple, viable solution. Using only a list of parameters passed to it, Optika can dynamically generate a GUI. This allows the user to specify parameters values in a fashion that is much more intuitive than the traditional 'input decks' used by some parameterized scientific applications. By leveraging the power of Optika, these scientific applications will become more accessible and thus allow their designers to reach a much wider audience while requiring minimal extra development effort.
Date: June 1, 2011
Creator: Nusbaum, Kurtis L.
Object Type: Report
System: The UNT Digital Library
Optika : a GUI framework for parameterized applications. (open access)

Optika : a GUI framework for parameterized applications.

None
Date: June 1, 2011
Creator: Nusbaum, Kurtis Lee
Object Type: Report
System: The UNT Digital Library
Visual Comfort Analysis of Innovative Interior and Exterior Shading Systems for Commercial Buildings using High Resolution Luminance Images (open access)

Visual Comfort Analysis of Innovative Interior and Exterior Shading Systems for Commercial Buildings using High Resolution Luminance Images

The objective of this study was to explore how calibrated high dynamic range (HDR) images (luminance maps) acquired in real world daylit environments can be used to characterize, evaluate, and compare visual comfort conditions of innovative facade shading and light-redirecting systems. Detailed (1536 x 1536 pixel) luminance maps were time-lapse acquired from two view positions in an unoccupied full scale testbed facility. These maps were analyzed using existing visual comfort metrics to quantify how innovative interior and exterior shading systems compare to conventional systems under real sun and sky conditions over a solstice-to-solstice test interval. The results provide a case study in the challenges and potential of methods of visualizing, evaluating and summarizing daily and seasonal variation of visual comfort conditions computed from large sets of image data.
Date: January 11, 2011
Creator: Konis, Kyle; Lee, Eleanor & Clear, Robert
Object Type: Article
System: The UNT Digital Library
Advanced Strategy Guideline: Air Distribution Basics and Duct Design (open access)

Advanced Strategy Guideline: Air Distribution Basics and Duct Design

This report discusses considerations for designing an air distribution system for an energy efficient house that requires less air volume to condition the space. Considering the HVAC system early in the design process will allow adequate space for equipment and ductwork and can result in cost savings. Principles discussed that will maximize occupant comfort include delivery of the proper amount of conditioned air for appropriate temperature mixing and uniformity without drafts, minimization of system noise, the impacts of pressure loss, efficient return air duct design, and supply air outlet placement, as well as duct layout, materials, and sizing.
Date: December 1, 2011
Creator: Burdick, A.
Object Type: Report
System: The UNT Digital Library
NNSA Nonproliferation Graduate Fellowship Program Annual Report June 2009 - May 2010 (open access)

NNSA Nonproliferation Graduate Fellowship Program Annual Report June 2009 - May 2010

In 2009, the Nonproliferation Graduate Fellowship Program (NGFP) completed its 17th successful year in support of the NNSA’s mission by developing future leaders in nonproliferation and promoting awareness of career opportunities. This annual report to reviews program activities from June 2009 through May 2010 - the fellowship term for the Class of 2009. Contents include: Welcome Letter (Mission Driven: It’s all about results), Introduction, Structure of the NGFP, Program Management Highlights, Annual Lifecycle, Class of 2009 Incoming Fellows, Orientation, Global Support of the Mission, Career Development, Management of the Fellows, Performance Highlights, Closing Ceremony, Where They Are Now, Alumni Highlight - Mission Success: Exceptional Leaders from the NGFP, Class of 2009 Fall Recruitment Activities, Established Partnerships, Face-to-Face, Recruiting Results, Interviews, Hiring and Clearances, Introducing the Class of 2010, Class of 2011 Recruitment Strategy, On the Horizon, Appendix A: Class of 2010 Fellow Biographies
Date: April 1, 2011
Creator: Berkman, Clarissa O. & Fankhauser, Jana G.
Object Type: Report
System: The UNT Digital Library
DFT-based materials and steel design at finite temperatures (open access)

DFT-based materials and steel design at finite temperatures

None
Date: June 1, 2011
Creator: Grabowski, B; Hickel, T; Kormann, F & Neugebauer, J
Object Type: Article
System: The UNT Digital Library
Multi-Scale Initial Conditions For Cosmological Simulations (open access)

Multi-Scale Initial Conditions For Cosmological Simulations

We discuss a new algorithm to generate multi-scale initial conditions with multiple levels of refinements for cosmological 'zoom-in' simulations. The method uses an adaptive convolution of Gaussian white noise with a real-space transfer function kernel together with an adaptive multi-grid Poisson solver to generate displacements and velocities following first- (1LPT) or second-order Lagrangian perturbation theory (2LPT). The new algorithm achieves rms relative errors of the order of 10{sup -4} for displacements and velocities in the refinement region and thus improves in terms of errors by about two orders of magnitude over previous approaches. In addition, errors are localized at coarse-fine boundaries and do not suffer from Fourier-space-induced interference ringing. An optional hybrid multi-grid and Fast Fourier Transform (FFT) based scheme is introduced which has identical Fourier-space behaviour as traditional approaches. Using a suite of re-simulations of a galaxy cluster halo our real-space-based approach is found to reproduce correlation functions, density profiles, key halo properties and subhalo abundances with per cent level accuracy. Finally, we generalize our approach for two-component baryon and dark-matter simulations and demonstrate that the power spectrum evolution is in excellent agreement with linear perturbation theory. For initial baryon density fields, it is suggested to use the local …
Date: November 4, 2011
Creator: Hahn, Oliver; /KIPAC, Menlo Park; Abel, Tom & /KIPAC, Menlo Park /ZAH, Heidelberg /HITS, Heidelberg
Object Type: Article
System: The UNT Digital Library
Stephen Jay Kline on systems, or physics, complex systems, and the gap between. (open access)

Stephen Jay Kline on systems, or physics, complex systems, and the gap between.

At the end of his life, Stephen Jay Kline, longtime professor of mechanical engineering at Stanford University, completed a book on how to address complex systems. The title of the book is 'Conceptual Foundations of Multi-Disciplinary Thinking' (1995), but the topic of the book is systems. Kline first establishes certain limits that are characteristic of our conscious minds. Kline then establishes a complexity measure for systems and uses that complexity measure to develop a hierarchy of systems. Kline then argues that our minds, due to their characteristic limitations, are unable to model the complex systems in that hierarchy. Computers are of no help to us here. Our attempts at modeling these complex systems are based on the way we successfully model some simple systems, in particular, 'inert, naturally-occurring' objects and processes, such as what is the focus of physics. But complex systems overwhelm such attempts. As a result, the best we can do in working with these complex systems is to use a heuristic, what Kline calls the 'Guideline for Complex Systems.' Kline documents the problems that have developed due to 'oversimple' system models and from the inappropriate application of a system model from one domain to another. One prominent …
Date: June 1, 2011
Creator: Campbell, Philip LaRoche
Object Type: Report
System: The UNT Digital Library
Background Report on Eastern Democratic Republic of the Congo (open access)

Background Report on Eastern Democratic Republic of the Congo

Each month, approximately 45,000 people die from violence, hunger, disease, and other effects of displacement as a result of war in the Democratic Republic of the Congo (DRC). The country is often said to be plagued by a 'resource curse.' During each period in history since its discovery by the West, the DRC has possessed the resources the world craves and the world has sought these without regard for the consequences to the Congolese people. The catastrophic consequences of Congo's history of natural resource exploitation are the direct and indirect death of millions of Congolese people. The current war in Congo is multi-causal in nature but explanations are often reduced to describing it as an ethic conflict based on objective grievance. Objective grievance such as inequality, ethnic tensions, land disputes, and lack of democracy do exist, but they are neither necessary nor sufficient to explain the cause of the violent conflict, and more importantly, they fall short in explaining why this conflict has continued for years. The reality is the conflict is an economic war in which the trade of conflict minerals, gold and the 3Ts (tin, tantalum, tungsten), is directly linked to the financial sustainability of the groups fighting …
Date: May 1, 2011
Creator: Warren, Tracy A
Object Type: Report
System: The UNT Digital Library
Iron Phosphate Glass-Containing Hanford Waste Simulant (open access)

Iron Phosphate Glass-Containing Hanford Waste Simulant

Resolution of the nation’s high level tank waste legacy requires the design, construction, and operation of large and technically complex one-of-a-kind processing waste treatment and vitrification facilities. While the ultimate limits for waste loading and melter efficiency have yet to be defined or realized, significant reductions in glass volumes for disposal and mission life may be possible with advancements in melter technologies and/or glass formulations. This test report describes the experimental results from a small-scale test using the research scale melter (RSM) at Pacific Northwest National Laboratory (PNNL) to demonstrate the viability of iron phosphate-based glass with a selected waste composition that is high in sulfates (4.37 wt% SO3). The primary objective of the test was to develop data to support a cost-benefit analysis as related to the implementation of phosphate-based glasses for Hanford low activity waste (LAW) and/or other high-level waste streams within the U.S. Department of Energy complex. The testing was performed by PNNL and supported by Idaho National Laboratory, Savannah River National Laboratory, and Mo-Sci Corporation.
Date: August 1, 2011
Creator: Sevigny, Gary J.; Kimura, Marcia L.; Fischer, Christopher M.; Schweiger, Michael J. & Kim, Dong-Sang
Object Type: Report
System: The UNT Digital Library
Peirce, pragmatism, and the right way of thinking. (open access)

Peirce, pragmatism, and the right way of thinking.

This report is a summary of and commentary on (a) the seven lectures that C. S. Peirce presented in 1903 on pragmatism and (b) a commentary by P. A. Turrisi, both of which are included in Pragmatism as a Principle and Method of Right Thinking: The 1903 Harvard Lectures on Pragmatism, edited by Turrisi [13]. Peirce is known as the founder of the philosophy of pragmatism and these lectures, given near the end of his life, represent his mature thoughts on the philosophy. Peirce's decomposition of thinking into abduction, deduction, and induction is among the important points in the lectures.
Date: August 1, 2011
Creator: Campbell, Philip LaRoche
Object Type: Report
System: The UNT Digital Library
Impact of post-event avoidance behavior on commercial facilities sector venues-literature review. (open access)

Impact of post-event avoidance behavior on commercial facilities sector venues-literature review.

The terrorist attacks of September 11, 2001 (9/11), focused a great deal of interest and concern on how individual and social perceptions of risk change behavior and subsequently affect commercial sector venues. Argonne conducted a review of the literature to identify studies that quantify the direct and indirect economic consequences of avoidance behaviors that result from terrorist attacks. Despite a growing amount of literature addressing terrorism impacts, relatively little is known about the causal relationships between risk perception, human avoidance behaviors, and the economic effects on commercial venues. Nevertheless, the technical and academic literature does provide some evidence, both directly and by inference, of the level and duration of post-event avoidance behaviors on commercial venues. Key findings are summarized in this Executive Summary. Also included as an appendix is a more detailed summary table of literature findings reproduced from the full report.
Date: March 24, 2011
Creator: Samsa, M. E.; Baldwin, T. E.; Berry, M. S.; Guzowski, L. B.; Martinez-Moyano, I.; Nieves, A. L. et al.
Object Type: Report
System: The UNT Digital Library
Nuclear Energy Advanced Modeling and Simulation (NEAMS) Waste Integrated Performance and Safety Codes (IPSC) : FY10 development and integration. (open access)

Nuclear Energy Advanced Modeling and Simulation (NEAMS) Waste Integrated Performance and Safety Codes (IPSC) : FY10 development and integration.

This report describes the progress in fiscal year 2010 in developing the Waste Integrated Performance and Safety Codes (IPSC) in support of the U.S. Department of Energy (DOE) Office of Nuclear Energy Advanced Modeling and Simulation (NEAMS) Campaign. The goal of the Waste IPSC is to develop an integrated suite of computational modeling and simulation capabilities to quantitatively assess the long-term performance of waste forms in the engineered and geologic environments of a radioactive waste storage or disposal system. The Waste IPSC will provide this simulation capability (1) for a range of disposal concepts, waste form types, engineered repository designs, and geologic settings, (2) for a range of time scales and distances, (3) with appropriate consideration of the inherent uncertainties, and (4) in accordance with robust verification, validation, and software quality requirements. Waste IPSC activities in fiscal year 2010 focused on specifying a challenge problem to demonstrate proof of concept, developing a verification and validation plan, and performing an initial gap analyses to identify candidate codes and tools to support the development and integration of the Waste IPSC. The current Waste IPSC strategy is to acquire and integrate the necessary Waste IPSC capabilities wherever feasible, and develop only those capabilities …
Date: February 1, 2011
Creator: Criscenti, Louise Jacqueline; Sassani, David Carl; Arguello, Jose Guadalupe, Jr.; Dewers, Thomas A.; Bouchard, Julie F.; Edwards, Harold Carter et al.
Object Type: Report
System: The UNT Digital Library