Physical Sciences and Mathematics Commons^™

Automated Nanocrystal Orientation And Phase Mapping In The Transmission Electron Microscope On The Basis Of Precession Electron Diffraction, Edgar F. Rauch, Joaquin Portillo, Stavros Nicolopoulos, Daniel Bultreys, Sergei Rouvimov, Peter Moeck

Physics Faculty Publications and Presentations

An automated technique for the mapping of nanocrystal phases and orientations in a transmission electron microscope is described. It is primarily based on the projected reciprocal lattice geometry that is extracted from electron diffraction spot patterns. Precession electron diffraction patterns are especially useful for this purpose. The required hardware allows for a scanning-precession movement of the primary electron beam on the crystalline sample and can be interfaced to any older or newer mid-voltage transmission electron microscope (TEM). Experimentally obtained crystal phase and orientation maps are shown for a variety of samples. Comprehensive commercial and open-access crystallographic databases may be used …

Gauge Invariance And Reciprocity In Quantum Mechanics, P.T. Leung, K. Young

Physics Faculty Publications and Presentations

Reciprocity in wave propagation usually refers to the symmetry of the Green's function under the interchange of the source and the observer coordinates, but this condition is not gauge invariant in quantum mechanics, a problem that is particularly significant in the presence of a vector potential. Several possible alternative criteria are given and analyzed with reference to different examples with nonzero magnetic fields and/or vector potentials, including the case of a multiply connected spatial domain. It is shown that the appropriate reciprocity criterion allows for specific phase factors separable into functions of the source and observer coordinates and that this …

Aerospace Section News, Hema Ramachandran

Sci-Tech News

The Aerospace Section of the Engineering Division encourages communication and cooperation among information professionals concerned with aerospace, aeronautical and related technologies. In addition, it fosters dialog with entities such as NASA, the AIAA and other important sources of technical data and bibliographical services.

Division Officers And Boards

Sci-Tech News

No abstract provided.

Lie Algebroid Structures On Double Vector Bundles And Representation Theory Of Lie Algebroids, Alfonso Gracia-Saz, Rajan Amit Mehta

Mathematics Sciences: Faculty Publications

A VB-algebroid is essentially defined as a Lie algebroid object in the category of vector bundles. There is a one-to-one correspondence between VB-algebroids and certain flat Lie algebroid superconnections, up to a natural notion of equivalence. In this setting, we are able to construct characteristic classes, which in special cases reproduce characteristic classes constructed by Crainic and Fernandes. We give a complete classification of regular VB-algebroids, and in the process we obtain another characteristic class of Lie algebroids that does not appear in the ordinary representation theory of Lie algebroids.

Forest Restoration In A Mixed-Ownership Landscape Under Climate Change, Catherine Ravenscroft, Robert M. Scheller, David J. Mladenoff, Mark A. White

Environmental Science and Management Faculty Publications and Presentations

The article presents a study regarding forest management associated with climate change. It mentions that preservation endeavors and restoration schemes should diminish current threats like unsuited forest management and development while integrating possible effects of climate change. It also stresses that an adaptive approach to management can be the most efficient strategy of forest restoration given the doubts of climate change impacts.

Western Rock Lobster Fishery Harvest Strategy And Decision Rules Framework Proposals. A Discussion Paper., Department Of Fisheries Western Australia

Fisheries management papers

This paper outlines proposals designed to be used in an updated and improved Harvest Strategy and Decision Rules Framework (referred to as the ‘Decision Rules’) that has been developed to meet the short and long term sustainability and economic needs of the West Coast Rock Lobster Managed Fishery. This approach represents international ‘best practice’ for fisheries management and is consistent with the Commonwealth Government’s Fisheries Harvest Strategy Policy1 .

A Test Of Pre-Main-Sequence Lithium Depletion Models, Jennifer Chun Ming Yee , '07, Eric L.N. Jensen

Physics & Astronomy Faculty Works

Despite the extensive study of lithium depletion during pre-main-sequence (PMS) contraction, studies of individual stars show discrepancies between ages determined from the Hertzsprung-Russell (H-R) diagram and ages determined from lithium depletion, indicating open questions in the PMS evolutionary models. To further test these models, we present high-resolution spectra for members of the beta Pictoris Moving Group (BPMG), which is young and nearby. We measure equivalent widths of the 6707.8 angstrom Li I line in these stars and use them to determine lithium abundances. We combine the lithium abundance with the predictions of PMS evolutionary models in order to calculate a …

Stable Spheromak Formation By Merging In An Oblate Flux Conserver, Timothy G. Gray , '01, Michael R. Brown, C. D. Cothran, G. Marklin, M. J. Schaffer

Physics & Astronomy Faculty Works

An axisymmetric spheromak formed by the dynamic merging of two smaller spheromaks of the same magnetic helicity in the Swarthmore Spheromak Experiment (SSX) [M. R. Brown, Phys. Plasmas 6, 1717 (1999)] has been observed and characterized. The spheromak is formed in an oblate (tilt stable), trapezoidal, 6 mm wall copper flux conserver in SSX, which is 0.5 m in diameter and L=0.4 m in length at its largest dimensions. This configuration is formed by cohelicity merging of two spheromaks (either both right-handed or both left-handed) in which the merging poloidal fluxes are parallel (i.e., no field reversal for reconnection to …

Wayne E. Sabbe Arkansas Soil Fertility Studies 2009, Nathan A. Slaton

Arkansas Agricultural Experiment Station Research Series

Rapid technological changes in crop management and production require that the research efforts also be presented in an expeditious manner. The contributions of soil fertility and fertilizers are major production factors in all Arkansas crops. The studies described within will allow producers to compare their practices with the university’s research efforts.

Efficient Cca-Secure Pke From Identity-Based Techniques, Junzuo Lai, Robert H. Deng, Shengli Liu, Weidong Kou

Research Collection School Of Computing and Information Systems

Boneh, Canetti, Halevi, and Katz showed a general method for constructing CCA-secure public key encryption (PKE) from any selective-ID CPA-secure identity-based encryption (IBE) schemes. Their approach treated IBE as a black box. Subsequently, Boyen, Mei, and Waters demonstrated how to build a direct CCA-secure PKE scheme from the Waters IBE scheme, which is adaptive-ID CPA secure. They made direct use of the underlying IBE structure, and required no cryptographic primitive other than the IBE scheme itself. However, their scheme requires long public key and the security reduction is loose. In this paper, we propose an efficient PKE scheme employing identity-based …

K-Anonymity In The Presence Of External Databases, Dimitris Sacharidis, Kyriakos Mouratidis, Dimitris Papadias

Research Collection School Of Computing and Information Systems

The concept of k-anonymity has received considerable attention due to the need of several organizations to release microdata without revealing the identity of individuals. Although all previous k-anonymity techniques assume the existence of a public database (PD) that can be used to breach privacy, none utilizes PD during the anonymization process. Specifically, existing generalization algorithms create anonymous tables using only the microdata table (MT) to be published, independently of the external knowledge available. This omission leads to high information loss. Motivated by this observation we first introduce the concept of k-join-anonymity (KJA), which permits more effective generalization to reduce the …

Probabilistic Public Key Encryption With Equality Test, Guomin Yang, Chik How Tan, Qiong Huang, Duncan S. Wong

Research Collection School Of Computing and Information Systems

We present a (probabilistic) public key encryption (PKE) scheme such that when being implemented in a bilinear group, anyone is able to check whether two ciphertexts are encryptions of the same message. Interestingly, bilinear map operations are not required in key generation, encryption or decryption procedures of the PKE scheme, but is only required when people want to do an equality test (on the encrypted messages) between two ciphertexts that may be generated using different public keys. We show that our PKE scheme can be used in different applications such as searchable encryption and partitioning encrypted data. Moreover, we show …

A Self-Organizing Neural Architecture Integrating Desire, Intention And Reinforcement Learning, Ah-Hwee Tan, Yu-Hong Feng, Yew-Soon Ong

Research Collection School Of Computing and Information Systems

This paper presents a self-organizing neural architecture that integrates the features of belief, desire, and intention (BDI) systems with reinforcement learning. Based on fusion Adaptive Resonance Theory (fusion ART), the proposed architecture provides a unified treatment for both intentional and reactive cognitive functionalities. Operating with a sense-act-learn paradigm, the low level reactive module is a fusion ART network that learns action and value policies across the sensory, motor, and feedback channels. During performance, the actions executed by the reactive module are tracked by a high level intention module (also a fusion ART network) that learns to associate sequences of actions …

Top-K Aggregation Queries Over Large Networks, Xifeng Yan, Bin He, Feida Zhu, Jiawei Han

Research Collection School Of Computing and Information Systems

Searching and mining large graphs today is critical to a variety of application domains, ranging from personalized recommendation in social networks, to searches for functional associations in biological pathways. In these domains, there is a need to perform aggregation operations on large-scale networks. Unfortunately the existing implementation of aggregation operations on relational databases does not guarantee superior performance in network space, especially when it involves edge traversals and joins of gigantic tables. In this paper, we investigate the neighborhood aggregation queries: Find nodes that have top-k highest aggregate values over their h-hop neighbors. While these basic queries are common in …

Medially: A Provenance-Aware Remote Health Monitoring Middleware, Atanu Roy Chowdhury, Ben Falchuk, Archan Misra

Research Collection School Of Computing and Information Systems

This paper presents MediAlly, a middleware for supporting energy-efficient, long-term remote health monitoring. Data is collected using physiological sensors and transported back to the middleware using a smart phone. The key to MediAlly's energy efficient operations lies in the adoption of an Activity Triggered Deep Monitoring (ATDM) paradigm, where data collection episodes are triggered only when the subject is determined to possess a specified context. MediAlly supports the on-demand collection of contextual provenance using a novel low-overhead provenance collection sub-system. The behaviour of this sub-system is configured using an application-defined context composition graph. The resulting provenance stream provides valuable insight …

Local Coordination Under Bounded Rationality: Coase Meets Simon, Finds Hayek, C. Jason Woodard

Research Collection School Of Computing and Information Systems

This paper explores strategic behavior in a network of firms using an agent-based model. The model exhibits a tension between economic efficiency and the stability of the network in the face of incentives to change its configuration. This tension is to be expected because the conditions of the Coase theorem are violated: the boundedly rational firms in the model lack the ability to discover efficient network configurations or achieve them through collective action. In computational experiments, as predicted by theory, firms frequently became locked into inefficient outcomes or endless cycles of mutual frustration. However, simple institutional innovations such as property …

Radio Emission From Substellar Companions Of Evolved Cool Stars., Richard Ignace, Mark Giroux, Donald Luttermoser

ETSU Faculty Works

A number of substellar companions to evolved cool stars have now been reported. Cool giants are distinct from their progenitor main-sequence low-mass stars in a number of ways. First, the mass loss rates of cool giant stars are orders of magnitude greater than for the late-type main-sequence stars. Secondly, on the cool side of the Linsky–Haisch ‘dividing line’, K and M giant stars are not X-ray sources, although they do show evidence for chromospheres. As a result, cool star winds are largely neutral for those spectral types, suggesting that planetary or brown dwarf magnetospheres will not be effective in standing …

Lake Mead National Recreation Area Vegetation Monitoring And Analysis: Final Project Report, Scott R. Abella, Margaret N. Rees

Vegetation Monitoring

Vegetation Monitoring and Analysis at Lake Mead National Recreation Area (NRA) was funded by the Multi-Species Habitat Conservation Plan, Southern Nevada Public Land Management Act, Lower Colorado River Multi-Species Conservation Program, and Lake Mead NRA base-funds. This Cooperative Task Agreement was awarded to the Public Lands Institute (PLI) at the University of Nevada, Las Vegas (UNLV) on September 30, 2006 with the term ending December 31, 2009, as modified. The primary purpose of this Task Agreement was to work within an interagency framework towards the accomplishment of three main vegetation management objectives. These three goals were to: (1) inventory, research …

What Is Clean Cities?, U.S. Department Of Energy

Publications (T)

Sponsored by the U.S. Department of Energy’s (DOE) Vehicle Technologies Program (VTP), Clean Cities is a government- industry partnership designed to reduce petroleum consumption in the transportation sector. Clean Cities contributes to the energy, environmental, and economic security of the United States by supporting local decisions to reduce our dependence on imported petroleum. Established in 1993 in response to the Energy Policy Act (EPAct) of 1992, the partnership provides tools and resources for voluntary, communitycentered programs to reduce consumption of petroleum-based fuels.

Electron-Impact-Ionization Cross Sections Of H₂ For Low Outgoing Electron Energies From 1 To 10 Ev, Ola A. Al-Hagan, Andrew James Murray, Christian V. Kaiser, James Colgan, Don H. Madison

Physics Faculty Research & Creative Works

Theoretical and experimental fully differential cross sections are presented for electron-impact ionization of molecular hydrogen in a plane perpendicular to the incident beam direction. The experimental data exhibit a maximum for 1-eV electrons detected 180° apart and a minimum for 10-eV electrons. We investigate the different physical effects which cause back-to-back scattering and demonstrate that, over the energy range from 10 to 1 eV, a direct transition is observed from a region where Wannier threshold physics is essentially unimportant to where it completely dominates.

Simultaneous Separation And Detection Of Cations And Anions Ion A Microfluidic Device With Suppressed Electroosmotic Flow And A Single Injection Point, B. R. Reschke, J. Schiffbauer, Boyd F. Edwards, A. T. Timperman

All Physics Faculty Publications

A rapid and simultaneous separation of cationic and anionic peptides and proteins in a glass microfluidic device that has been covalently modified with a neutral poly(ethylene glycol) (PEG) coating to minimize protein adsorption is presented. The features of the device allow samples that contain both anions and cations to be introduced from a central flow stream and separated in different channels with different outlets—all in the presence of low electroosmotic flow (EOF) imparted by the PEG coating. The analytes are electrophoretically extracted from a central hydrodynamic stream and electrophoretically separated in two different channels, in which pressure driven flow has …

Creating An Immersive Game World With Evolutionary Fuzzy Cognitive Maps, Yundong Cai, Ah-Hwee Tan, Zhiqi Shen, Boyang Li

Research Collection School Of Computing and Information Systems

An increasing number of serious games have been developed to enhance the user experiences in education and training. In order to bridge the gap of game experiences in the virtual environment and in the real life, it is crucial to generate believable characters and contexts in real-time. However, the variables to be simulated for a large-scale serious game are numerous. These variables are involved in complex causal relationships and their values change over time. In view that world modeling has not been well addressed with conventional models, this paper uses a computational model Evolutionary Fuzzy Cognitive Map (EFCM) to model …

A Multi-Key Pirate Decoder Against Traitor Tracing Schemes, Yongdong Wu, Robert H. Deng

Research Collection School Of Computing and Information Systems

In this paper we introduce an architecture for a multi-key pirate decoder which employs decryption keys from multiple traitors. The decoder has built-in monitoring and self protection functionalities and is capable of defeating most multiple-round based traitor tracing schemes such as the schemes based on the black-box confirmation method. In particular, the proposed pirate decoder is customized to defeat the private key and the public key fully collusion resistant traitor tracing (FTT) schemes, respectively. We show how the decoder prolongs a trace process so that the tracer has to give up his effort. FTT schemes are designed to identify all …

Preference Queries In Large Multi-Cost Transportation Networks, Kyriakos Mouratidis, Yimin Lin, Man Lung Yiu

Research Collection School Of Computing and Information Systems

Research on spatial network databases has so far considered that there is a single cost value associated with each road segment of the network. In most real-world situations, however, there may exist multiple cost types involved in transportation decision making. For example, the different costs of a road segment could be its Euclidean length, the driving time, the walking time, possible toll fee, etc. The relative significance of these cost types may vary from user to user. In this paper we consider such multi-cost transportation networks (MCN), where each edge (road segment) is associated with multiple cost values. We formulate …

Reverberation-Chamber Test Environment For Outdoor Urban Wireless Propagation Studies, Helge Fielitz, Kate A. Remley, Christopher L. Holloway, Qian Zhang, Qiong Wu, David W. Matolak

Faculty Publications

We introduce a test environment to replicate the well-known clustering of reflections in power delay profiles arising from late-time delays and reflections. Urban wireless propagation environments are known to exhibit such clustering. The test setup combines discrete reflections generated by a fading simulator with the continuous distribution of reflections created in a reverberation chamber. We describe measurements made in an urban environment in Denver, CO, that illustrate these multiple distributions of reflections. Our comparison of measurements made in the urban environment to those made in the new test environment shows good agreement.

Development Of Regional Wind Resource And Wind Plant Output Datasets: Final Subcontract Report, 3tier

Publications (E)

This is the Final Report for the project “Development of Regional Wind Resource and Wind Plant Output Datasets“(NREL subcontract number: AAM-8-77556-01 under prime contract number: DE-AC36-99GO10337). The report covers the period of the contract from October 15, 2007 through March 15, 2009. The final delivered outcomes of this project include:

• This report detailing the work produced.

• 30 validation reports for the purpose of tuning the mesoscale models.

• The numerical weather prediction (NWP) simulations for 2004-2006 in NetCDF format with a spatial resolution of one arc-minute and a temporal resolution of ten minutes.

• 30,544 original sites and …

Barrier Coatings For Thin Film Solar Cells: Final Subcontract Report, L. C. Olsen

Publications (E)

This program has involved investigations of the stability of CdTe and copper-indium-gallium-diselenide (CIGS) solar cells under damp heat conditions and effects of barrier coatings. CdTe and CIGS cells were subjected to environmental conditions characterized by 60ºC and 90% relative humidity (60/90), and to some extent 85ºC and 85 % relative humidity (85/85). Barrier coating technology developed at PNNL for OLEDs was used to investigate approaches to encapsulation of the two types of thin film solar cells. Moisture barriers consisting of multi-layer coatings involving alternating layers of polymer and aluminum oxide were deposited directly onto the front surface of CIGS cells …

Solar Power And The Electric Grid, Energy Analysis, Nrel Energy Analysis

Publications (E)

In today’s electricity generation system, different resources make different contributions to the electricity grid. This fact sheet illustrates the roles of distributed and centralized renewable energy technologies, particularly solar power, and how they will contribute to the future electricity system. The advantages of a diversified mix of power generation systems are highlighted.

Consortia Focused On Photovoltaic R&D, Manufacturing, And Testing: A Review Of Existing Models And Structures, Charlie Coggeshall, Robert M. Margolis

Publications (E)

As the U.S. Department of Energy's (DOE's) Solar Energy Technologies Program prepares to initiate a new cost-shared research and development (R&D) effort on photovoltaic (PV) manufacturing, it is useful to review the experience to date with consortia focused on PV R&D, manufacturing, and testing. Information was gathered for this report by conducting interviews and accessing Web sites of 14 U.S. consortia and four European consortia, each with either a primary focus on or an emerging interest in PV technology R&D, manufacturing, or testing. Additional input was collected from several workshops held by the DOE and National Academy of Sciences (NAS) …