Physical Sciences and Mathematics Commons^™

Psodascript: Applying Advanced Language Constructs To Open-Source Phylogenetic Search, Hyrum Carroll, Mark J. Clement, Jonathan Krein, Quinn O. Snell, Adam R. Teichert

Faculty Publications

Due to the immensity of phylogenetic tree space for large data sets, researches must rely on heuristic searches to infer reasonable phylogenies. By designing meta-searches which appropriately combine a variety of heuristics and parameter settings, researchers can significantly improve the performance of heuristic searches. Advanced language constructs in the open-source PSODA project—including variables, mathematical and logical expressions, conditional statements, and user-defined commands—give researchers a better framework for the exploration and exploitation of phylogenetic meta-search algorithms. PSODA’s approach to scripting meta-search algorithms is unique among open-source packages and addresses several limitations of other phylogenetic applications.

Control Of Nonholonomic Mobile Robot Formations Using Neural Networks, Jagannathan Sarangapani, Travis Alan Dierks

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper the control of formations of multiple nonholonomic mobile robots is attempted by integrating a kinematic controller with a neural network (NN) computed-torque controller. A combined kinematic/torque control law is developed for leader-follower based formation control using backstepping in order to accommodate the dynamics of the robots and the formation in contrast with kinematic-based formation controllers. The NN is introduced to approximate the dynamics of the follower as well as its leader using online weight tuning. It is shown using Lyapunov theory that the errors for the entire formation are uniformly ultimately bounded, and numerical results are provided.

Geogram 2007, David J. Keeling Editor, Wku Department Of Geography And Geology

Earth, Environmental, and Atmospheric Sciences Publications

No abstract provided.

Report On Mini-Workshop “Bringing Margins Science To The Classroom”, Cathy Manduca, Jeffrey G. Ryan, Don Reed

Geology Faculty Publications

MARGINS has been awarded an NSF Course, Curriculum, and Laboratory Improvement (CCLI) grant to bring MARGINS research into widespread use in undergraduate teaching in ways that showcase the integrated, multidisciplinary approach that is characteristic of modern, front-line geoscience research. In collaboration with the Science Education Resource Center (SERC) at Carleton College, the project is developing a web-based collection of teaching materials referred to as “Mini-Lessons” (http://serc.carleton.edu/margins). Mini-Lessons range in scope from something as simple as the use of MARGINS science to illustrate a lecture to multi-day lab projects that capitalize on the MARGINS Data Repository. An exciting aspect of this …

Attosecond Pulse Carrier-Envelope Phase Effects On Ionized Electron Momentum And Energy Distributions, Liang-You Peng, Anthony F. Starace

Anthony F. Starace Publications

We analyze carrier-envelope phase (CEP) effects on electron wave-packet momentum and energy spectra produced by one or two few-cycle attosecond xuv pulses. The few-cycle attosecond pulses are assumed to have arbitrary phases. We predict CEP effects on ionized electron wave-packet momentum distributions produced by attosecond pulses having durations comparable to those obtained by Sansone et al. [Science 314, 443 (2006)]. The onset of significant CEP effects is predicted to occur for attosecond pulse field strengths close to those possible with current experimental capabilities. Our results are based on single-active-electron solutions of the three-dimensional, time-dependent Schrödinger equation including atomic potentials …

Ground Water Dependence Of Endangered Ecosystems: Nebraska’S Eastern Saline Wetlands, F. Edwin Harvey, Jerry F. Ayers, David C. Gosselin

School of Natural Resources: Faculty Publications

Many endangered or threatened ecosystems depend on ground water for their survival. Nebraska’s saline wetlands, home to a number of endangered species, are ecosystems whose development, sustenance, and survival depend on saline ground water discharge at the surface. This study demonstrates that the saline conditions present within the eastern Nebraska saline wetlands result from the upwelling of saline ground water from within the underlying Dakota Aquifer and deeper underlying formations of Pennsylvanian age. Over thousands to tens of thousands of years, saline ground water has migrated over regional scale flowpaths from recharge zones in the west to the present-day discharge …

Eesi Newsletter, No. 3, Oct. 2007, Energy & Environmental Security Initiative (University Of Colorado Boulder)

EESI: The Energy & Environmental Security Initiative [Newsletter] (2007)

No abstract provided.

Soil Survey Of The Bettink Dairy Farm, Riverway Road, Northcliffe, Peter J. Tille, Tilwin Westrup

Resource management technical reports

This soil survey of the Bettink dairy farm in Northcliffe, Western Australia aimed to: provide detailed soil descriptions to add to information associated with the environment in which the dairy industry in Western Australia is located; collect soil samples at predetermined standard depths from documented farm locations for nutrient analysis; map soils with similar characteristics based on description and analysis.

Generation Of Molecular Complexity From Cyclooctatetraene: Synthesis Of A Protected 2-(3′-Carboxy-2′-Benzoylcyclopentyl)Glycine, Subhabrata Chaudhury, Sergey Lindeman, William Donaldson

Chemistry Faculty Research and Publications

Synthesis of a protected 2-(3′-carboxycyclopentyl)glycine rac-11, possessing four contiguous chiral carbons, was accomplished in six steps (20% yield) from the hydrocarbon cyclooctatetraene.

The Urban Heat Island Mitigation Impact Screening Tool (Mist), David J. Sailor, Nikolaas Dietsch

Mechanical and Materials Engineering Faculty Publications and Presentations

A web-based software tool has been developed to assist urban planners and air quality management officials in assessing the potential of urban heat island mitigation strategies to affect the urban climate, air quality, and energy consumption within their cities. The user of the tool can select from over 170 US cities for which to conduct the analysis, and can specify city-wide changes in surface reflectivity and/or vegetative cover. The Mitigation Impact Screening Tool (MIST) then extrapolates results from a suite of simulations for 20 cities to estimate air temperature changes associated with the specified changes in surface characteristics for the …

Sketchwizard: Wizard Of Oz Prototyping Of Pen-Based User Interfaces, Richard C. Davis, T. Scott Saponas, Michael Shilman, James A. Landay

Research Collection School Of Computing and Information Systems

SketchWizard allows designers to create Wizard of Oz prototypes of pen-based user interfaces in the early stages of design. In the past, designers have been inhibited from participating in the design of pen-based interfaces because of the inadequacy of paper prototypes and the difficulty of developing functional prototypes. In SketchWizard, designers and end users share a drawing canvas between two computers, allowing the designer to simulate the behavior of recognition or other technologies. Special editing features are provided to help designers respond quickly to end-user input. This paper describes the SketchWizard system and presents two evaluations of our approach. The …

Upper Limit Map Of A Background Of Gravitational Waves, B. P. Abbott, R. Abbott, Mario C. Diaz, R. Grosso, Soumya Mohanty, Soma Mukherjee, Cristina V. Torres

Physics and Astronomy Faculty Publications and Presentations

We searched for an anisotropic background of gravitational waves using data from the LIGO S4 science run and a method that is optimized for point sources. This is appropriate if, for example, the gravitational wave background is dominated by a small number of distinct astrophysical sources. No signal was seen. Upper limit maps were produced assuming two different power laws for the source strain power spectrum. For an f−3 power law and using the 50 Hz to 1.8 kHz band the upper limits on the source strain power spectrum vary between 1.2×10−48  Hz−1 (100  Hz/f)3 and 1.2×10−47  Hz−1 (100  Hz/f)3, …

Effects Of Human Choices On Characteristics Of Urban Ecosystems, Lawrence A. Baker, Anthony J. Brazel, Loren Bryne, Alex Felson, Morgan Grove, Kristina Hill, Kristen C. Nelson, Jason Walker, Vivek Shandas

Institute for Sustainable Solutions Publications and Presentations

Most urban ecology in cities remains an "ecology in cities" rather than an "ecology of cities." Accomplishing the latter requires the inclusion of humans within the concept of "ecosystem," both how humans alter the properties of urban ecosystems and how these alterations in turn influence human well-being. These influences are both direct (e.g., physiological and psychological influences on the human organism) and indirect, by influencing ecosystem sustainability. For the 2007 ESA meeting, Larry Baker, Loren Byrne, Jason Walker, and Alex Felson organized a symposium to address the relationships among human choices and urban ecosystems. In the introductory talk of this …

Option-Based Risk Management: A Field Study Of Sequential Information Technology Investment Decisions, Michel Benaroch, Mark Jeffery, Robert John Kauffman, Sandeep Shah

Research Collection School Of Computing and Information Systems

This field study research evaluates the viability of applying an option-based risk management (OBRiM) framework, and its accompanying theoretical perspective and methodology, to real-world sequential information technology (IT) investment problems. These problems involve alternative investment structures that bear different risk profiles for the firm, and also may improve the payoffs of the associated projects and the organization's performance. We sought to surface the costs, benefits, and risks associated with a complex sequential investment setting that has the key features that OBRiM treats. We combine traditional, purchased real options that subsequently create strategic flexibility for the decision maker, with implicit or …

Efficient Discovery Of Frequent Approximate Sequential Patterns, Feida Zhu, Xifeng Yan, Jiawei Han, Philip S. Yu

Research Collection School Of Computing and Information Systems

We propose an efficient algorithm for mining frequent approximate sequential patterns under the Hamming distance model. Our algorithm gains its efficiency by adopting a "break-down-and-build-up" methodology. The "breakdown" is based on the observation that all occurrences of a frequent pattern can be classified into groups, which we call strands. We developed efficient algorithms to quickly mine out all strands by iterative growth. In the "build-up" stage, these strands are grouped up to form the support sets from which all approximate patterns would be identified. A salient feature of our algorithm is its ability to grow the frequent patterns by iteratively …

Performance Of Network-Coding In Multi-Rate Wireless Environments For Multicast Applications, Luiz F. M. Viera, Archan Misra, Mario Gerla

Research Collection School Of Computing and Information Systems

This paper investigates the interaction between net-work coding and link-layer transmission rate diversity in multi-hop wireless networks. By appropriately mixing data packets at intermediate nodes, network coding allows a single multicast flow to achieve higher throughput to a set of receivers. Broadcast applications can also exploit link-layer rate diversity, whereby individual nodes can transmit at faster rates at the expense of corresponding smaller coverage area. We first demonstrate how combining rate-diversity with network coding can provide a larger capacity for data dissemination of a single multicast flow, and how consideration of rate diversity is critical for maximizing system throughput. We …

Desarrollo Turístico Y Sustentabilidad: Caso Villa Pehuenia Y La Comunidad Mapuche Puel, Sasha Shahidi

Independent Study Project (ISP) Collection

With limited resources and overpopulation on a global level, sustainable development is the only way that human beings will be able to survive on this earth. The problem is that the dominant model of development stresses the importance of economic profits in the short term and far too often exploits natural resources and less powerful cultural groups. This creates dangerous long-term affects as natural resources and indigenous cultures that depend on them continue to disappear with no plan, or possibility, to replace them. Sustainability seeks the least negative impacts possible on the natural environment and indigenous cultures in order to …

Searches For Periodic Gravitational Waves From Unknown Isolated Sources And Scorpius X-1: Results From The Second Ligo Science Run, B. P. Abbott, R. Abbott, Mario C. Diaz, R. Grosso, Wm. R. Johnston, Soumya Mohanty, Soma Mukherjee, Cristina V. Torres

Physics and Astronomy Faculty Publications and Presentations

We carry out two searches for periodic gravitational waves using the most sensitive few hours of data from the second LIGO science run. Both searches exploit fully coherent matched filtering and cover wide areas of parameter space, an innovation over previous analyses which requires considerable algorithm development and computational power. The first search is targeted at isolated, previously unknown neutron stars, covers the entire sky in the frequency band 160–728.8 Hz, and assumes a frequency derivative of less than 4×10−10  Hz/s. The second search targets the accreting neutron star in the low-mass x-ray binary Scorpius X-1 and covers the frequency …

Npake+: A Hierarchical Group Password-Authenticated Key Exchange Protocol Using Different Passwords, Zhiguo Wan, Robert H. Deng, Feng Bao, Bart Preneel

Research Collection School Of Computing and Information Systems

Although two-party password-authenticated key exchange (PAKE) protocols have been intensively studied in recent years, group PAKE protocols have received little attention. In this paper, we propose a hierarchical group PAKE protocol nPAKE+ protocol under the setting where each party shares an independent password with a trusted server. The nPAKE+ protocol is a novel combination of the hierarchical key tree structure and the password-based Diffie-Hellman exchange, and hence it achieves substantial gain in computation efficiency. In particular, the computation cost for each client in our protocol is only O(logn). Additionally, the hierarchical feature of nPAKE+ enables every subgroup obtains their own …

Om-Based Video Shot Retrieval By One-To-One Matching, Yuxin Peng, Chong-Wah Ngo, Jianguo Xiao

Research Collection School Of Computing and Information Systems

This paper proposes a new approach for shot-based retrieval by optimal matching (OM), which provides an effective mechanism for the similarity measure and ranking of shots by one-to-one matching. In the proposed approach, a weighted bipartite graph is constructed to model the color similarity between two shots. Then OM based on Kuhn-Munkres algorithm is employed to compute the maximum weight of a constructed bipartite graph as the shot similarity value by one-to-one matching among frames. To improve the speed efficiency of OM, two improved algorithms are also proposed: bipartite graph construction based on subshots and bipartite graph construction based on …

Implementing Uganda’S National Wetlands Policy: A Case Study Of Kabale District, Sophie Glass

Independent Study Project (ISP) Collection

Uganda’s “National Policy for the Conservation and Management of Wetland Resources” was launched in 1995 to promote the protection of Uganda’s wetlands in order to sustain their ecological and socioeconomic functions. Despite the formal policy, wetlands continue to be drained and converted. This report examines factors that account for the divide between the National Wetlands Policy and reality. Six weeks were spent researching the challenges associated with implementing the National Wetlands Policy. Kabale District was used as a case-study to better understand the issues that institutions and stakeholders face when trying to abide by the precepts of the policy. Rapid …

Watered Down: The Intersection And Integration Of Tourism Development And Water Resource Management In Marrakech, Morocco, Alison Maassen

Independent Study Project (ISP) Collection

No abstract provided.

The Price Of Gold: The Environmental Impacts Of Toxic Chemicals In Gold Mining, Adam Goetz

Independent Study Project (ISP) Collection

The role of mercury and cyanide in gold mining has become a hot topic in Mongolia in the past few years. In the past few months, the government has launched a crackdown on the illegal use of these chemicals in response to the contamination of Khongor soum’s drinking water which resulted from an illegal mining operation. However, there are many more sites throughout the country that are in need of cleaning as a result of the illegal use of these chemicals by small companies as well as individual miners.

This paper examines the role of a variety of different views …

Why Logging? A Value Assessment Of Forestry Uses In The Huon Forest District, Ryan Bailey

Independent Study Project (ISP) Collection

The Huon Forest District comprises 762,800 hectares of forests in southwest Tasmania, with 128,900 hectares of that total designated as state forest managed by Forestry Tasmania. These forests are used primarily for wood production, although tourism, carbon storage, leatherwood honey and the specialty timbers industry are competing for access to these forests. This study examines the socio-economic values of these uses and determines whether the Huon Forest District is being utilized efficiently.

To accomplish this, an extensive literature review of past research was conducted. This information supplemented 7 semi-structured interviews that were conducted with experts from the forestry industry, tourism …

Accounting For Ecosystem Flows: Setting A Standard For Australian Industries To Make Sustainable Decisions, Emily Gilbert

Independent Study Project (ISP) Collection

This paper explains the System of Environmental and Economic Accounting’s (SEEA) approach to environmental accounting flow systems and how this system is now being utilized in the creation of new Australian standards of accounting. The first part of the paper discusses in depth different accounting systems, primarily physical and hybrid accounting systems, as they relate to the measures set forth by the SEEA. The second part analyzes the differences between the SEEA’s gross accounting system in comparison to the Intergovernmental Panel on Climate Change’s (IPCC) net accounting system. This includes a type of “pro-con” way of looking at which is …

Ontogenetic Changes In Feeding Ecology And Habitat Of The Damselfish Neoglyphidodon Melas At Lizard Island, Great Barrier Reef, Sai-Wing Chan

Independent Study Project (ISP) Collection

This study examines ontogenetic shift in habitat and feeding ecology of the black damselfish, Neoglyphidodon melas in three patch reef sites at Lizard Island, Great Barrier Reef. This rarely studied species is unique in its coprophagous relationship with the faeces of the giant clam Tridacna gigas. Distribution and habitat composition between three sites and two reef zones was estimated with 48 Visual Belt and Point Intercept Transects. 80 Focal Animal Studies revealed specific foraging strategies and aggressive behaviours. The timing of this study permitted the inclusion of juvenile recruits resulting in a more complete and comprehensive study across developmental stages. …

Distribution Of Ultraviolet-Absorbing Sunscreen Compounds Across The Body Surface Of Two Species Of Scaridae, Elizabeth Cerny-Chipman

Independent Study Project (ISP) Collection

Ultraviolet radiation has far-reaching effects in marine ecosystems, but many marine organisms have UV-absorbing compounds that protect them from sun-induced damage. The mucus of coral reef fish has been found to contain mycosporine-like amino acids that absorb UV light from 309-360 nm. Using UV spectrophotometry, we examined whether fish are able to allocate these MAA sunscreen compounds to areas of the body that receive the most UV radiation. We compared absorbance spectra of mucus from the body surface of dorsal, ventral, caudal and head areas in two species of Scaridae (Scarus schlegeli and Chlorurus sordidus) from Coral Bay, Western Australia. …

Gaps In The Cloud Cover? : Comparing Extinction Measures In Spiral Disks., Benne W. Holwerda, M. Meyer, M. W. Regan, D. Calzetti, K. D. Gordon, J. D. Smith, D. Dale, C. W. Engelbracht, T. Jarrett, M. Thornley, C. Bot, B. Buckalew, R. C. Kennicutt, R. A. Gonzalez

Faculty and Staff Scholarship

Dust in galaxies can be mapped either by the FIR/submillimeter emission, the optical or infrared reddening of starlight, or the extinction of a known background source. We compare two dust extinction measurements for a set of 15 sections in 13 nearby galaxies to determine the scale of the dusty interstellar medium ( ISM ) responsible for disk opacity: one using stellar reddening and the other a known background source. In our earlier papers, we presented extinction measurements of 29 galaxies, based on calibrated counts of distant background objects identified though foreground disks in Hubble Space Telescope WFPC2 images. For the …

Fundamental Emission Via Wave Advection From A Collapsing Wave Packet In Electromagnetic Strong Plasma Turbulence, Fredrick A. Jenet, A. Melatos, P. A. Robinson

Physics and Astronomy Faculty Publications and Presentations

Zakharov simulations of nonlinear wave collapse in continuously driven two-dimensional, electromagnetic strong plasma turbulence with electron thermal speeds v⩾0.01c show that for v≲0.1c, dipole radiation occurs near the plasma frequency, mainly near arrest, but for v≳0.1c, a new mechanism applies in which energy oscillates between trapped Langmuir and transverse modes until collapse is arrested, after which trapped transverse waves are advected into incoherent interpacket turbulence by an expanding annular density well, where they detrap. The multipole structure, Poynting flux, source current, and radiation angular momentum are computed.

Luminescent Charge-Transfer Platinum(Ii) Metallacycle, Fei Hua, Solen Kinayyigit, Aaron A. Rachford, Elena A. Shikhova, Sebastien Goeb, John R. Cable, Christopher J. Adams, Kristin Kirschbaum, A. Alan Pinkerton, Felix N. Castellano

Chemistry Faculty Publications

The photophysical and electrochemical properties of a platinum(II) diimine complex bearing the bidentate diacetylide ligand tolan-2,2'-diacetylide (tda), Pt(dbbpy)(tda) [dbbpy = 4,4'-di-tert-butyl-2,2'-bipyridine] (1), are compared with two reference compounds, Pt(dbbpy)(C CPh)(2) (2) and Pt(dppp)tda [dppp = 1,3-bis(diphenylphosphino)propane] (3), respectively, The X-ray crystal structure of 1 is reported, which illustrates the nearly perfect square planarity exhibited by this metallacycle. Chromophore 2 possesses low-lying charge-transfer excited states analogous to 1, whereas structure 3 lacks such excited states but features a low-lying platinum-perturbed tda intraligand triplet manifold. In CH2Cl2, 1 exhibits a broad emission centered at 562 nm at ambient temperature, similar to 2, …