Physical Sciences and Mathematics Commons^™

A Dearth Of Planetary Transits In The Direction Of Ngc 6940, Ben Hood, Andrew Collier Cameron, Stephen R. Kane, D. M. Bramich, Keith Horne, Rachel A. Street, I. A. Bond, A. J. Penny, Y. Tsapras, A. Quirrenbach, N. Safizadeh, D. Mitchell, J. Cooke

Physics

We present results of our survey for planetary transits in the field of NGC 6940. We think nearly all of our observed stars are field stars. We have obtained high precision (∼3–10 mmag at the bright end) photometric observations of ∼50 000 stars spanning 18 nights in an attempt to identify low-amplitude and short-period transit events. We have used a matched filter analysis to identify 14 stars that show multiple events and four stars that show single transits. Of these 18 candidates, we have identified two that should be further researched. However, none of the candidates is a convincing hot …

Neutron Multiplicity Measurements For The Afci Program Quarterly Progress Report April-June 2005, Denis Beller

Transmutation Sciences Physics (TRP)

This project was developed to test a Russian-built Neutron Multiplicity Detector System (NMDS) for measuring neutrons generated in a central target by a variety of accelerators. To assist in experiment design and evaluation, we use the most advanced high energy radiation transport code, MCNPX, to model experiments. Experimental results are compared to computational predictions and discrepancies are investigated. Initial plans were to conduct experiments using a 70-MeV proton cyclotron at the Crocker Nuclear Laboratory at the University of California at Davis and/or a 20 to 40 MeV electron linac (linear accelerator) at the Idaho Accelerator Center (IAC) at Idaho State …

The Electrochemical Separation Of Curium And Americium: Quaterly Report April - June, 2005, David W. Hatchett, Kenneth Czerwinski

Separations Campaign (TRP)

This research report outlines the current status and progress associated with the electrochemical separation of Curium and Americium.

Results

• We have completed the electrochemical investigation in of the Ce³⁺/Ce⁴⁺ redox couple and have determined the optimum experimental conditions.

• Computer modeling of the cerium using the JChess speciation-modeling program has been completed for the Ce redox couple. Traditional complexing ligands such as EDTA, oxalate, NTA, phosphate, acetate, and sulfate have been purchased and will be used to initiate the complexation and electrochemical characterization.

• Electrochemical investigations have continued on the Eu²⁺/Eu³⁺ redox …

Dissolution, Reactor, And Environmental Behavior Of Zro2-Mgo Inert Fuel Matrix: Quarterly Report, April 2005 To June 2005, Earl Wolfram, Thomas Hartmann, Kenneth Czerwinski

Fuels Campaign (TRP)

This project will examine inert matrix fuels containing ZrO₂ and MgO as the inert matrix, with the relative amount of MgO varied from 30% to 70% in ZrO₂. Reactor physics calculations will be used to examine suitable quantities of burnable poisons from the candidate elements Gd, Er, or Hf with reactor grade Pu providing the fissile component, with up to 10 % of ²³⁹Pu. Ceramics will be synthesized and characterized based on the reactor physics results. The solubility the fuel ceramics, in reactor conditions, reprocessing conditions, and repository conditions, will be investigated in a manner to …

Effects Of Surfactants On The Thermal And Fire Properties Of Poly(Methyl Methacrylate)/Clay Nanocomposites, Panchatapa Jash, Charles A. Wilkie

Chemistry Faculty Research and Publications

Nanocomposites of poly(methyl methacrylate) (PMMA) with layered silicates and with polyhedral oligosilsesquioxanes (POSS) were prepared by bulk polymerization. The thermal and fire stabilities of the various organically-modified clay and POSS nanocomposites were evaluated using both thermogravimetric analysis (TGA) and cone calorimetry. Thermogravimetric analysis is not a good criteria for evaluating nanocomposite formation but cone calorimetry can be. For montmorillonite systems, when more than 4% clay is present, the expected reduction in peak heat release rate is observed. For hectorite, a minimum of 6% clay concentration is required to achieve the same reduction in peak heat release rate. POSS has the …

Correspondence Expansion For Wide Baseline Stereo, Parris K. Egbert, Kevin L. Steele

Faculty Publications

We present a new method for generating large numbers of accurate point correspondences between two wide baseline images. This is important for structure-from-motion algorithms, which rely on many correct matches to reduce error in the derived geometric structure. Given a small initial correspondence set we iteratively expand the set with nearby points exhibiting strong affine correlation, and then we constrain the set to an epipolar geometry using RANSAC. A key point to our algorithm is to allow a high error tolerance in the constraint, allowing the correspondence set to expand into many areas of an image before applying a lower …

Active Contours Using A Constraint-Based Implicit Representation, Weiming Liu, Bryan S. Morse, Kalpathi Subramanian, Terry S. Yoo

Faculty Publications

We present a new constraint-based implicit active contour, which shares desirable properties of both parametric and implicit active contours. Like parametric approaches, their representation is compact and can be manipulated interactively. Like other implicit approaches, they can naturally adapt to non-simple topologies. Unlike implicit approaches using level-set methods, representation of the contour does not require a dense mesh. Instead, it is based on specified on-curve and off-curve constraints, which are interpolated using radial basis functions. These constraints are evolved according to specified forces drawn from the relevant literature of both parametric and implicit approaches. This new type of active contour …

A Scenario-Based Performance Evaluation Of Multicast Routing Protocols For Ad Hoc Networks, Manoj Pandey, Daniel Zappala

Faculty Publications

Current ad hoc multicast routing protocols have been designed to build and maintain a tree or mesh in the face of a mobile environment, with fast reaction to network changes in order to minimize packet loss. However, the performance of these protocols has not been adequately examined under realistic scenarios. Existing performance studies generally use a single, simple mobility model, with low density and often very low traffic rates. In this paper we explore the performance of ad hoc multicast routing protocols under scenarios that include realistic mobility patterns, high density and high traffic load. We use these scenarios to …

Techno-Economic Evaluation Of Conventional And Membrane-Based Pretreatment Before Reverse Osmosis, Shamma Ahmed Rashid Al-Malek

Theses

In this thesis, a technological and economical comparison was conducted on both conventional and membrane based pre-treatment before reverse osmosis desalination. In order to produce high quality water at the design recovery ratio, reverse osmosis membranes should receive high quality feed water in terms of turbidity, suspended solids, and biological matters. Conventional pre-treatment schemes of media and cartridge filters after coagulation chambers have been used for years. Due to the poor performance and decline in reverse osmosis recovery, membrane based pre-treatment has emerged and has been under research and study in the recent years. Few conventional pre-treatment reverse osmosis plants …

Biological Notes On Ground-Nesting Digger Wasps From Western Nebraska, Robert W. Matthews, Janice R. Matthews

The Prairie Naturalist

Nine species of sphecid wasps nesting in sparsely vegetated sandy soils near Ogallala, Keith County, Nebraska were studied during June 2003. The first records of the nest and prey of Cerceris clypeata gnarina Banks and Tachysphex williamsi R. Bohart are presented. Two species of weevils, Baris striata Say and B. subsimilis Casey, were prey of C. clypeata gnarina, with 12 to 22 individuals stocked per cell. Because B. subsimilis is a biological control agent for thistle, this finding is a caution to researchers not to ignore the potential impact of predatory wasps on the community. The single nest of T …

Non-Stretchable Pseudo-Visibility Graphs, Ileana Streinu

Computer Science: Faculty Publications

We exhibit a family of graphs which can be realized as pseudo-visibility graphs of pseudo-polygons, but not of straight-line polygons. The example is based on the characterization of vertex-edge pseudo-visibility graphs of O'Rourke and Streinu [Proc. ACM Symp. Comput. Geometry, Nice, France, 1997, pp. 119-128] and extends a recent result of the author [Proc. ACM Symp. Comput. Geometry, Miami Beach, 1999, pp. 274-280] on non-stretchable vertex-edge visibility graphs. We construct a pseudo-visibility graph for which there exists a unique compatible vertex-edge visibility graph, which is then shown to be non-stretchable. The construction is then extended to an infinite family. © …

The Navigation Potential Of Signals Of Opportunity-Based Time Difference Of Arrival Measurements, Kenneth A. Fisher

Theses and Dissertations

This research introduces the concept of navigation potential, NP, to quantify the intrinsic ability to navigate using a given signal. NP theory is a new, information theory-like concept that provides a theoretical performance limit on estimating navigation parameters from a received signal that is modeled through a stochastic mapping of the transmitted signal and measurement noise. NP theory is applied to SOP-based TDOA systems in general as well as for the Gaussian case. Furthermore, the NP is found for a received signal consisting of the transmitted signal, multiple delayed and attenuated replicas of the transmitted signal, and measurement noise. Multipath-based …

Evaluation Of Optimized Variable Area Transect Sampling Using Totally Enumerated Field Data Sets, Richard M. Engeman, Ryan M. Nielson, Robert T. Sugihara

United States Department of Agriculture Wildlife Services: Staff Publications

Plotless density estimators (PDEs) can be efficient alternatives to quadrat sampling for estimating the density of stationary objects. Variable area transect (VAT) sampling had been identified, and optimized relative to effort, in previous Monte Carlo simulated population studies as a low-labor field method that demonstrated superior estimation properties among many PDEs considered. However, natural populations tend to be much more complex and less predictable in spatial distribution than computer generated populations. Therefore, we carried out a Monte Carlo simulation study that used 17 fully enumerated field populations rather than simulated populations. These natural populations represented a variety of population densities …

Leiocephalus Carinatus Armouri (Northern Curly-Tailed). Entanglement In Human-Made Materials, Christopher L. Dean, Henry T. Smith, Richard M. Engeman, Walter E. Meshaka Jr.

United States Department of Agriculture Wildlife Services: Staff Publications

No abstract provided.

Sensory Modality Used By Coyotes In Responding To Antipredator Compounds In The Blood Of Texas Horned Lizards, Wade C. Sherbrooke, J. Russell Mason

United States Department of Agriculture Wildlife Services: Staff Publications

We investigated the hypothesis that the squirting of blood from orbital sinuses by Texas horned lizards (Phrynosoma cornutum) is an antipredator defense against some mammalian species. Coyotes (Canis latrans) were tested for the first time. As expected, Texas horned lizards squirted blood in response to coyote attacks, and coyotes exhibited startle response, avoidance response, or both as a result of these events. Whereas lizard carcasses mixed into normal foodmash elicited regurgitation by coyotes, possibly due to physical effects, blood of horned lizards similarly mixed into food did not. Coyote responses to simulated squirts of 5 compounds, …

A Framework For Routing And Topological Decision-Making Within A Transformational Communications Architecture, Alexander I. Smith

Theses and Dissertations

A Transformational Communications Architecture (TCA) has been proposed by the US government with the goal of creating "an Internet in the sky." This thesis presents a framework which places user requirements at the heart of routing and topological decision-making within the TCA. It provides new terminology to describe data transmissions and link characteristics and an approach to formulating cost functions to better meet user needs. The framework is intended to stimulate interest and focus efforts on how to meet military specific requirements by taking advantage of the TCA's diverse capabilities and topology. Cost functions using newly-defined parameters are simulated and …

The John Muir Newsletter, Summer 2005, The John Muir Center For Environmental Studies

Muir Center Newsletters (1981-2015)

EjOi HVfeRSnY OF' THE PACIFIC, STOCKTON. CA : Volume 15, Numbers Summer 2005::= r ORLD IOUR Introduction by W. R. Swagerty Director, John Muir Center John Muir's World Tour of 1903-1904 is not well known for good reason. The journals from this trip have never been published and Muir wrote no specific book from his European travels. The manuscript journals are part of the John Muir Papers within Holt-Atherton Special Collections here at Pacific. The journals are lengthy and were transcribed by Muir scholar, Linnie Marsh Wolfe, sometime in the 1940s or 1950s. They have also been microfilmed as part …

A Memorial To D. Craig Edwards (1939-2004), H. Allen Curran, Hilary Edwards Lithgow

Geosciences: Faculty Publications

No abstract provided.

Fit-To-Fight: Waist Vs. Waist/Height Measurements To Determine An Individual's Fitness Level A Study In Statistical Regression And Analysis, Steven J. Swiderski

Theses and Dissertations

Air Force members are to be tested for fitness by measuring their abdominal circumference, counting the number of sit-ups and push-ups they can accomplish, and the time it takes them to run 1 and miles. The abdominal measurement is a "one-size-fits-all" fitness standard. This research determines that a person's waist-to-height ratio is a better measurement than the waist measurement to estimate an individual's fitness level. This research estimates that all of the variables used to proxy fitness (Gender, Age, Height, Waist Circumference, Waist-to-Height Ratio, Push-Ups, and Sit-Ups) are statistically significant and do represent good estimators of physical fitness. This research …

Breaking Public Key Cryptosystems On Tamper Resistant Devices In The Presence Of Transient Faults, Feng Bao, Robert H. Deng, Y. Han, A. Jeng, Arcot Desai Narasimhalu, T. Ngair

Research Collection School Of Computing and Information Systems

In this paper we present a method of attacking public-key cryptosystems (PKCs) on tamper resistant devices. The attack makes use of transient faults and seems applicable to many types of PKCs. In particular, we show how to attack the RSA, the E1Gamal signature scheme, the Schnorr signature scheme, and the DSA. We also present some possible methods to counter the attack.

Co Line Emission And Absorption From The Hl Tauri Disk-Where Is All The Dust?, Sean D. Brittain, Terrence W. Rettig, Theodore Simon, Craig Kulesa

Publications

We present high-resolution infrared spectra of HL Tau, a heavily embedded young star. The spectra exhibit broad emission lines of 12CO gas-phase molecules, as well as narrow absorption lines of 12CO, 13CO, and C18O. The broad emission lines of vibrationally excited 12CO are dominated by the hot (T ~ 1500 K) inner disk. The narrow absorption lines of CO are found to originate from the circumstellar gas at a temperature of ~100 K. The 12CO column density for this cooler material [(7.5 ± 0.2) × 1018 cm-2] indicates a large column of absorbing gas along the line of sight. In …

Erratum: Nonrelativistic Qed Approach To The Bound-Electron G Factor (Phys. Rev. Lett. (2004) 93 (150401)), Krzysztof Pachucki, Ulrich D. Jentschura, Vladimir A. Yerokhin

Physics Faculty Research & Creative Works

No abstract provided.

Analysis Of A Wi-Fi Hotspot Network, David P. Blinn, Tristan Henderson, David Kotz

Dartmouth Scholarship

Wireless hotspot networks have become increasingly popular in recent years as a means of providing Internet access in public areas such as restaurants and airports. In this paper we present the first study of such a hotspot network. We examine five weeks of SNMP traces from the Verizon Wi-Fi HotSpot network in Manhattan. We find that far more cards associated to the network than logged into it. Most clients used the network infrequently and visited few APs. AP utilization was uneven and the network displayed some unusual patterns in traffic load. Some characteristics were similar to those previously observed in …

Modeling Users' Mobility Among Wifi Access Points, Minkyong Kim, David Kotz

Dartmouth Scholarship

Modeling movements of users is important for simulating wireless networks, but current models often do not reflect real movements. Using real mobility traces, we can build a mobility model that reflects reality. In building a mobility model, it is important to note that while the number of handheld wireless devices is constantly increasing, laptops are still the majority in most cases. As a laptop is often disconnected from the network while a user is moving, it is not feasible to extract the exact path of the user from network messages. Thus, instead of modeling individual user's movements, we model movements …

Capturing Design Patterns For Performance Issues In Database-Driven Web Applications, Osama Mabroul Khaled

Archived Theses and Dissertations

The Design patterns technology is a new research topic which aims at helping with communicating technical knowledge in a standard non-technical format. People coming from different technical backgrounds can share this knowledge and apply it in their own way. For example, pieces of designs could be the same for different applications but they get implemented using different programming languages. On the other hand, web applications are becoming more widely spread, especially e-commerce ones, which make light returns on investment and achieve good relations between the companies and the customers. To stabilize this relationship, a web application must have a good …

Parallel Versus Iterated: Comparing Population Oriented And Chained Sequential Simulated Annealing Approaches To Cost-Based Abduction, Heba Abdallah Amer

Archived Theses and Dissertations

Stochastic search techniques are used to solve NP-hard combinatorial optimization problems. Simulated annealing, genetic algorithms and hybridization of both, all attempt to find the best solution with minimal cost and time. Guided Evolutionary Simulated Annealing is one technique of such hybridization. It is based on evolutionary programming where a number of simulated annealing chains are working in a generation to find the optimum solution for a problem. Abduction is the problem of finding the best explanation to a given set of observations. In AI, this has been modeled by a set of hypotheses that need to be assumed to prove …

Detecting Malicious Vbscripts Using Anomaly Host Based Ids Based On Principal Component Analysis (Pca), Racha El Sokkary

Archived Theses and Dissertations

Intrusion detection research over the last twenty years has focused on the threat of individuals illegally hacking into systems. Nowadays, intrusion threat to computer systems has changed radically. Instead of dealing with hackers, most current works focus on defending the system against code-driven attacks. Today’s web script codes such as VBScript are receiving increasing focus as a backdoor for attacking many computers through e-mail attachments or infected web sites. The nature of these malicious codes is that they can spread widely causing serious damages to many applications. Moreover, the majority of anti-virus tools used today are able to detect known …

Modelling Continuum Optical And Ultraviolet Polarization Of Active Galactic Nuclei, René W. Goosmann, C. Martin Gaskell

Department of Physics and Astronomy: Faculty Publications

We present results from a new Monte Carlo radiative transfer computer code, STOKES, developed to model polarization induced by scattering off free electrons and dust grains. STOKES is freely available on the web and can be used to model scattering in a wide variety of astrophysical situations. For edge-on (type-2) viewing positions, the polarization produced by a dusty torus alone is largely wavelength-independent.

This is because the torus is optically thick and the change in albedo with wavelength is slight. Wavelength-independent polarization therefore does not necessarily imply electron scattering. We are able to fully explain wavelength independent type-2 polarization without …

Synergy Between Nanocomposite Formation And Low Levels Of Bromine On Fire Retardancy In Polystyrenes, Grace Chigwada, Panchatapa Jash, David D. Jiang, Charles A. Wilkie

Chemistry Faculty Research and Publications

An organically-modified clay has been prepared using ammonium salts which contain an oligomeric material consisting of vinylbenzyl chloride, styrene and dibromostyrene. The presence of dibromostyrene enhances the flame retardancy of polystyrene nanocomposites compared to both the virgin polymer and polystyrene nanocomposites prepared from non-halogen-containing organically-modified clays. The nanocomposites were prepared both by bulk polymerization and melt blending and they were evaluated by X-ray diffraction, transmission electron microscopy, thermogravimetric analysis and cone calorimetry measurements. Bulk polymerization produced nanocomposites with reduced peak heat release rate, reduced total heat release and improved thermal stability. It is noteworthy that all these improvements were obtained …

Learning Outcomes Oriented Assessment Methods In An Active Learning Environment, Arcot Desai Narasimhalu

Research Collection School Of Computing and Information Systems

Singapore Management University uses interactive seminar style teaching in class rooms. Most of its students hail from Singapore and are generally new to active learning and constructive participation in the seminar style classes. This paper reports findings from a freshmen first term course titled IS 101: Seminar for ISM Majors.