Results for "Dana S. Balser"

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An 8.5 GHz Arecibo survey of Carbon Recombination Lines toward Ultra-compact \HII regions: Physical properties of dense molecular materialJan 29 2005We report here on a survey of carbon recombination lines (RLs) near 8.5 GHz toward 17 ultra-compact \HII regions (\UCHII s). Carbon RLs are detected in 11 directions, indicating the presence of dense photodissociation regions (PDRs) associated with the ... More
Diffuse Ionized Gas in the Milky Way DiskSep 26 2017We analyze the diffuse ionized gas (DIG) in the first Galactic quadrant from l=18deg to 40deg using radio recombination line (RRL) data from the Green Bank Telescope. These data allow us to distinguish DIG emission from HII region emission and thus study ... More
Unveiling Extragalactic Star Formation Using Radio Recombination Lines: An EVLA Pilot Study with NGC 253Jun 23 2011Radio recombination lines (RRLs) are powerful, extinction-free diagnostics of the ionized gas in young, star-forming regions. Unfortunately, these lines are difficult to detect in external galaxies. We present the results of EVLA observations of the RRL ... More
A Green Bank Telescope Survey of Large Galactic HII RegionsOct 20 2017As part of our ongoing HII Region Discovery Survey (HRDS), we report the Green Bank Telescope detection of 148 new angularly-large Galactic HII regions in radio recombination line (RRL) emission. Our targets are located at a declination greater than -45deg., ... More
Hydrogen Radio Recombination Line Emission from M51 and NGC628May 29 2018We report the discovery of hydrogen radio recombination line (RRL) emission from two galaxies with star formation rates (SFRs) similar to that of the Milky Way: M51 and NGC628. We use the Green Bank Telescope (GBT) to measure $\sim$15 Hn$\alpha$ recombination ... More
H-, He-like recombination spectra III: $n$-changing collisions in highly-excited Rydberg states and their impact on the radio, IR and optical recombination linesMar 13 2019Mar 18 2019At intermediate to high densities, electron (de-)excitation collisions are the dominant process for populating or depopulating high Rydberg states. In particular, the accurate knowledge of the energy changing ($n$-changing) collisional rates is determinant ... More
The Chemical Evolution of HeliumAug 21 2006We report on measurements of the 4He abundance toward the outer Galaxy HII region S206 with the NRAO Green Bank telescope. Observations of hydrogen and helium radio recombination lines between 8-10 GHz were made toward the peak radio continuum position ... More
The Southern HII Region Discovery Survey I: The Bright CatalogDec 12 2018The census of Galactic HII regions is vastly incomplete in the Southern sky. We use the Australia Telescope Compact Array (ATCA) to observe 4-10 GHz radio continuum and hydrogen radio recombination line (RRL) emission from candidate HII regions in the ... More
Limits on Turbulent HI Fluctuations Towards PSR B0329+54 On Scales Between 0.0025 and 12.5 AUJun 02 2005We have measured the HI absorption towards pulsar B0329+54 using the Green Bank Telescope during 18 epochs between 2002 June 30 and 2003 October 10. Three observing epochs consisted of a continuous period of 20 hours each, while fifteen epochs were 1-2 ... More
The Arecibo HII Region Discovery SurveySep 21 2012We report the detection of radio recombination line emission (RRL) using the Arecibo Observatory at X-band (9GHz, 3cm) from 37 previously unknown HII regions in the Galactic zone 66 deg. > l > 31 deg. and |b| < 1 deg. This Arecibo HII Region Discovery ... More
CO Isotopes in Planetary NebulaeFeb 25 2002Standard stellar evolution theory is inconsistent with the observed isotopic carbon ratio, 12C/13C, in evolved stars. This theory is also inconsistent with the 3He/H abundance ratios observed in Galactic HII regions, when combined with chemical evolution ... More
Rate of Convergence for Cardy's FormulaOct 15 2012May 02 2014We show that crossing probabilities in 2D critical site percolation on the triangular lattice in a piecewise analytic Jordan domain converge with power law rate in the mesh size to their limit given by the Cardy-Smirnov formula. We use this result to ... More
The Green Bank Telescope Galactic H II Region Discovery SurveyJun 30 2010We discovered a large population of previously unknown Galactic H II regions by using the Green Bank Telescope to detect their hydrogen radio recombination line emission. Since recombination lines are optically thin at 3 cm wavelength, we can detect H ... More
The Green Bank Telescope H II Region Discovery Survey: IV. Helium and Carbon Recombination LinesDec 10 2012The Green Bank Telescope H II Region Discovery Survey (GBT HRDS) found hundreds of previously unknown Galactic regions of massive star formation by detecting hydrogen radio recombination line (RRL) emission from candidate H II region targets. Since the ... More
The Green Bank Telescope HII Region Discovery Survey II. The Source CatalogMar 25 2011The Green Bank Telescope HII Region Discovery Survey has doubled the number of known HII regions in the Galactic zone 343deg.\leql\leq67deg. with |b|\leq1deg. We detected 603 discrete hydrogen radio recombination line (RRL) components at 9GHz (3cm) from ... More
3-He in the Milky Way Interstellar Medium: Ionization StructureJun 13 2007The cosmic abundance of the 3-He isotope has important implications for many fields of astrophysics. We are using the 8.665 GHz hyperfine transition of 3-He+ to determine the 3-He/H abundance in Milky Way HII regions and planetary nebulae. This is one ... More
Summability of solutions of the heat equation with inhomogeneous thermal conductivity in two variablesFeb 27 2009We investigate Gevrey order and 1-summability properties of the formal solution of a general heat equation in two variables. In particular, we give necessary and sufficient conditions for the 1-summability of the solution in a given direction. When restricted ... More
The Detection of 3He+ in a Planetary Nebula Using the VLANov 16 2005We used the VLA to search for 3He+ emission from two Galactic planetary nebulae (PNe): NGC6572 and J320}. Standard stellar models predict that the 3He/H abundance ratios for PNe should be 1-2 orders of magnitude higher than the primordial value (3He/H ... More
Untangling the Recombination Line Emission from HII Regions with Multiple Velocity ComponentsJul 20 2015HII regions are the ionized spheres surrounding high-mass stars. They are ideal targets for tracing Galactic structure because they are predominantly found in spiral arms and have high luminosities at infrared and radio wavelengths. In the Green Bank ... More
The Green Bank Telescope HII Region Discovery Survey: III. Kinematic DistancesMay 18 2012Using the HI Emission/Absorption method, we resolve the kinematic distance ambiguity and derive distances for 149 of 182 (82%) HII regions discovered by the Green Bank Telescope HII Region Discovery Survey (GBT HRDS). The HRDS is an X-band (9GHz, 3cm) ... More
HII Region Ionization of the Interstellar Medium: A Case Study of NGC 7538May 09 2016Using data from the Green Bank Telescope, we analyze the radio continuum (free-free) and radio recombination line (RRL) emission of the compact HII region NGC 7538 (Sharpless 158). We detect extended radio continuum and hydrogen RRL emission beyond the ... More
Azimuthal Metallicity Structure in the Milky Way DiskMay 15 2015Elemental abundance patterns in the Galactic disk constrain theories of the formation and evolution of the Milky Way. HII region abundances are the result of billions of years of chemical evolution. We made radio recombination line and continuum measurements ... More
HII Region Metallicity Distribution in the Milky Way DiskJun 08 2011The distribution of metals in the Galaxy provides important information about galaxy formation and evolution. HII regions are the most luminous objects in the Milky Way at mid-infrared to radio wavelengths and can be seen across the entire Galactic disk. ... More
Radio Recombination Lines in Galactic HII RegionsMar 06 2006We report radio recombination line (RRL) and continuum observations of a sample of 106 Galactic HII regions made with the NRAO 140 Foot radio telescope in Green Bank, WV. We believe this to be the most sensitive RRL survey ever made for a sample this ... More
Radio continuum observations of local star-forming galaxies using the Caltech Continuum Backend on the Green Bank TelescopeNov 11 2013Nov 14 2013We observed radio continuum emission in 27 local (D < 70 Mpc) star-forming galaxies with the Robert C. Byrd Green Bank Telescope between 26 GHz and 40 GHz using the Caltech Continuum Backend. We obtained detections for 22 of these galaxies at all four ... More
The WISE Catalog of Galactic HII RegionsDec 21 2013Using data from the all-sky Wide-Field Infrared Survey Explorer (WISE) satellite, we made a catalog of over 8000 Galactic HII regions and HII region candidates by searching for their characteristic mid-infrared (MIR) morphology. WISE has sufficient sensitivity ... More
Tracing the Spiral Structure of the Outer Milky Way with Dense Atomic Hydrogen GasJun 30 2017We present a new face-on map of dense neutral atomic hydrogen (HI) gas in the outer Galaxy. Our map has been produced from the Leiden/Argentine/Bonn (LAB) HI 21-cm line all-sky survey by finding intensity maxima along every line of sight and then by projecting ... More
Finding Distant Galactic HII RegionsOct 26 2015The WISE Catalog of Galactic HII Regions contains $\sim2000$ HII region candidates lacking ionized gas spectroscopic observations. All candidates have the characteristic HII region mid-infrared morphology of WISE $12\,\,\mu\,m$ emission surrounding $22\,\mu\,m$ ... More
H-, He-like recombination spectra III: $n$-changing collisions in highly-excited Rydberg states and their impact on the radio, IR and optical recombination linesMar 13 2019At intermediate to high densities, electron (de-)excitation collisions are the dominant process for populating or depopulating high Rydberg states. In particular, the accurate knowledge of the energy changing ($n$-changing) collisional rates is determinant ... More
Magnetic Field Strengths in Photodissociation RegionsNov 23 2015We measure carbon radio recombination line (RRL) emission at 5.3 GHz toward four HII regions with the Green Bank Telescope (GBT) to determine the magnetic field strength in the photodissociation region (PDR) that surrounds the ionized gas. Roshi (2007) ... More
Universal Minimal Flows of Groups of Automorphisms of Uncountable StructuresNov 21 2011It is a well-known fact, that the greatest ambit for a topological group $G$ is the Samuel compactification of $G$ with respect to the right uniformity on $G.$ We apply the original destription by Samuel from 1948 to give a simple computation of the universal ... More
Carbon Monoxide Observations Toward Star Forming Regions in the Outer Scutum-Centaurus Spiral ArmNov 16 2017The Outer Scutum-Centaurus arm (OSC) is the most distant molecular spiral arm known in the Milky Way. The OSC may be the very distant end of the well-known Scutum-Centaurus arm, which stretches from the end of the Galactic bar to the outer Galaxy. At ... More
Science with an ngVLA: Radio Recombination Lines from HII RegionsOct 15 2018The ngVLA will create a Galaxy-wide, volume-limited sample of HII regions; solve some long standing problems in the physics of HII regions; and provide an extinction-free star formation tracer in nearby galaxies.
The focusing energy-critical nonlinear wave equation with random initial dataMar 18 2019We consider the focusing energy-critical quintic nonlinear wave equation in three dimensional Euclidean space. It is known that this equation admits a one-parameter family of radial stationary solutions, called solitons, which can be viewed as a curve ... More
Tensor products with bounded continuous functionsJul 09 2003We study that natural inclusions $C^b(X) \tensor A$ into $C^b(X,A)$ and $C^b(X, C^b(Y))$ into $C^b(X \times Y)$. In particular, excepting trivial cases, both these maps are isomorphisms only when $X$ and $Y$ are pseudocompact. This implies a result of ... More
Diagram calculus for a type affine $C$ Temperley--Lieb algebra, IIJan 21 2011Dec 31 2017In a previous paper, we presented an infinite dimensional associative diagram algebra that satisfies the relations of the generalized Temperley--Lieb algebra having a basis indexed by the fully commutative elements of the Coxeter group of type affine ... More
Gowers' Ramsey Theorem with multiple operations and dynamics of the homeomorphism group of the Lelek fanNov 19 2014Feb 14 2017We generalize the finite version of Gowers' Ramsey theorem to multiple tetris-like operations and apply it to show that a group of homeomorphisms that preserve a "typical" linear order of branches of the Lelek fan, a compact connected metric space with ... More
Path integrals, SUSY QM and the Atiyah-Singer index theorem for twisted DiracMay 23 2016Jan 05 2017Feynman's time-slicing construction approximates the path integral by a product, determined by a partition of a finite time interval, of approximate propagators. This paper formulates general conditions to impose on a short-time approximation to the propagator ... More
A Rigorous Path Integral for N=1 Supersymmetic Quantum Mechanics on a Riemannian ManifoldJul 11 2012Mar 28 2013Following Feynman's prescription for constructing a path integral representation of the propagator of a quantum theory, a short-time approximation to the propagator for imaginary time, N=1 supersymmetric quantum mechanics on a compact, even-dimensional ... More
Detection of Voigt Spectral Line Profiles of Hydrogen Radio Recombination Lines toward Sagittarius B2(N)Feb 19 2010We report the detection of Voigt spectral line profiles of radio recombination lines (RRLs) toward Sagittarius B2(N) with the 100-m Green Bank Telescope (GBT). At radio wavelengths, astronomical spectra are highly populated with RRLs, which serve as ideal ... More
Wavelet Based Dictionaries for Dimensionality Reduction of ECG SignalsNov 13 2018Dimensionality reduction of ECG signals is considered within the framework of sparse representation. The approach constructs the signal model by selecting elementary components from a redundant dictionary via a greedy strategy. The proposed wavelet dictionaries ... More
Convexity theorems for semisimple symmetric spacesJan 06 2014Mar 09 2015We prove a remarkable generalization of a convexity theorem for semisimple symmetric spaces G/H established earlier in 1986 by the second named author. The latter result generalized Kostant's non-linear convexity theorem for the Iwasawa decomposition ... More
Convex rank 1 subsets of Euclidean buildings (of type $A_2$)Oct 30 2006For a Euclidean building $X$ of type $A_{2}$, we classify the 0-dimensional subbuildings $A$ of $\partial_{T}X$ that occur as the asymptotic boundary of closed convex subsets. In particular, we show that triviality of the holonomy of a triple (of points ... More
Learning Bayesian Network Structure from Massive Datasets: The "Sparse Candidate" AlgorithmJan 23 2013Learning Bayesian networks is often cast as an optimization problem, where the computational task is to find a structure that maximizes a statistically motivated score. By and large, existing learning tools address this optimization problem using standard ... More
Towards a classification of CMC-1 Trinoids in hyperbolic space via conjugate surfacesOct 24 2003Oct 01 2004We derive necessary conditions on the parameters of the ends of a CMC-1 trinoid in hyperbolic 3-space $H^{3}$ with symmetry plane by passing to its conjugate minimal surface. Together with Daniel's results, this yields a classification of generic symmetric ... More
Two-Phase Heating in Flaring LoopsFeb 02 2018We analyze and model a C5.7 two-ribbon solar flare observed by SDO, Hinode and GOES on 2011 December 26. The flare is made of many loops formed and heated successively over one and half hours, and their footpoints are brightened in the UV 1600 A before ... More
The Arboricity Captures the Complexity of Sampling EdgesFeb 21 2019In this paper, we revisit the problem of sampling edges in an unknown graph $G = (V, E)$ from a distribution that is (pointwise) almost uniform over $E$. We consider the case where there is some a priori upper bound on the arboriciy of $G$. Given query ... More
Bayesian Active Learning for Collaborative Task Specification Using Equivalence RegionsJan 28 2019Specifying complex task behaviours while ensuring good robot performance may be difficult for untrained users. We study a framework for users to specify rules for acceptable behaviour in a shared environment such as industrial facilities. As non-expert ... More
Schur's Lemma for Coupled Reducibility and Coupled NormalityNov 20 2018Nov 29 2018Let $\mathcal A = \{A_{ij} \}_{i, j \in \mathcal I}$, where $\mathcal I$ is an index set, be a doubly indexed family of matrices, where $A_{ij}$ is $n_i \times n_j$. For each $i \in \mathcal I$, let $\mathcal V_i$ be an $n_i$-dimensional vector space. ... More
Temporal Variability of Lunar Exospheric Helium During January 2012 from LRO/LAMPSep 14 2012We report observations of the lunar helium exosphere made between December 29, 2011, and January 26, 2012, with the Lyman Alpha Mapping Project (LAMP) ultraviolet spectrograph on NASA's Lunar Reconnaissance Orbiter Mission (LRO). The observations were ... More
Polygons with prescribed Gauss map in Hadamard spaces and Euclidean buildingsDec 02 2004We show that given a stable weighted configuration on the asymptotic boundary of a locally compact Hadamard space, there is a polygon with Gauss map prescribed by the given weighted configuration if the configuration is stable. Moreover, the same result ... More
Phase Coexistence and Slow Mixing for the Hard-Core Model on Z^2Nov 27 2012In the hard-core model on a finite graph we are given a parameter lambda>0, and an independent set I arises with probability proportional to lambda^|I|. On infinite graphs a Gibbs distribution is defined as a suitable limit with the correct conditional ... More
Phase coexistence and torpid mixing in the 3-coloring model on Z^dOct 16 2012We show that for all sufficiently large d, the uniform proper 3-coloring model (in physics called the 3-state antiferromagnetic Potts model at zero temperature) on Z^d admits multiple maximal-entropy Gibbs measures. This is a consequence of the following ... More
Axiomatizing Category Theory in Free LogicSep 06 2016Sep 14 2016Starting from a generalization of the standard axioms for a monoid we present a stepwise development of various, mutually equivalent foundational axiom systems for category theory. Our axiom sets have been formalized in the Isabelle/HOL interactive proof ... More
Provable and practical approximations for the degree distribution using sublinear graph samplesOct 24 2017Aug 28 2018The degree distribution is one of the most fundamental properties used in the analysis of massive graphs. There is a large literature on graph sampling, where the goal is to estimate properties (especially the degree distribution) of a large graph through ... More
Groupoid equivalence and the associated iterated crossed productJun 10 2012Jul 24 2012Given groupoids $G$ and $H$ and a $(G,H)$-equivalence $X$ we may form the transformation groupoid $G\ltimes X\rtimes H$. Given a separable groupoid dynamical system $(A,G\ltimes X\rtimes H,\omega)$ we may restrict $\omega$ to an action of $G\ltimes X$ ... More
Axiomatizing Category Theory in Free LogicSep 06 2016Oct 12 2018Starting from a generalization of the standard axioms for a monoid we present a stepwise development of various, mutually equivalent foundational axiom systems for category theory. Our axiom sets have been formalized in the Isabelle/HOL interactive proof ... More
Out-Of-Focus Holography at the Green Bank TelescopeDec 10 2006Mar 31 2007We describe phase-retrieval holography measurements of the 100-m diameter Green Bank Telescope using astronomical sources and an astronomical receiver operating at a wavelength of 7 mm. We use the technique with parameterization of the aperture in terms ... More
Constructing Near Spanning Trees with Few Local InspectionsFeb 02 2015Feb 03 2015Constructing a spanning tree of a graph is one of the most basic tasks in graph theory. Motivated by several recent studies of local graph algorithms, we consider the following variant of this problem. Let G be a connected bounded-degree graph. Given ... More
Kinematic Decoupling of Globular Clusters with Extended Horizontal-BranchApr 04 2007About 25% of the Milky Way globular clusters (GCs) exhibit unusually extended color distribution of stars in the horizontal-branch (HB) phase. This phenomenon is now best understood as due to the presence of helium enhanced second generation subpopulations, ... More
Algebraic Properties of Generalized Graph Laplacians: Resistor Networks, Critical Groups, and Homological AlgebraApr 24 2016Jan 10 2017We propose an algebraic framework for generalized graph Laplacians which unifies the study of resistor networks, the critical group, and the eigenvalues of the Laplacian and adjacency matrices. Given a graph with boundary $G$ together with a generalized ... More
Centers of convex subsets of buildingsOct 20 2004We prove that two dimensional convex subsets of spherical buildings are either buildings or have a center.
Building-like spacesOct 20 2004We study convex subsets of buildings, discuss some structural features and derive several characterizations of buildings.
Rigorous path integrals for supersymmetric quantum mechanics: completing the path integral proof of the index theoremMay 01 2018Many introductory courses in quantum mechanics include Feynman's time-slicing definition of the path integral, with a complete derivation of the propagator in the simplest of cases. However, attempts to generalize this, for instance to non-quadratic potentials, ... More
Equivalence and Disintegration Theorems for Fell Bundles and their C*-algebrasJun 05 2008Aug 18 2008We study the C*-algebras of Fell bundles. In particular, we prove the analogue of Renault's disintegration theorem for groupoids. As in the groupoid case, this result is the key step in proving a deep equivalence theorem for the C*-algebras of Fell bundles. ... More
A Simple Convex Layers AlgorithmFeb 22 2017Mar 16 2017Given a set of $n$ points $P$ in the plane, the first layer $L_1$ of $P$ is formed by the points that appear on $P$'s convex hull. In general, a point belongs to layer $L_i$, if it lies on the convex hull of the set $P \setminus \bigcup_{j<i}\{L_j\}$. ... More
The Electron Temperature Gradient in the Galactic DiskSep 01 2006We derive the electron temperature gradient in the Galactic disk using a sample of HII regions that spans Galactocentric distances 0--17 kpc. The electron temperature was calculated using high precision radio recombination line and continuum observations ... More
The Dixmier-Douady Class of Groupoid Crossed ProductsSep 11 2002We give a formula for the Dixmier-Douady class of a continuous-trace groupoid crossed product that arises from an action of a locally trivial, proper, principal groupoid on a bundle of elementary $C^*$-algebras that satisfies Fell's condition.
Renault's Equivalence Theorem for Groupoid Crossed ProductsJul 24 2007Jun 05 2008We provide an exposition and proof of Renault's equivalence theorem for crossed products by locally Hausdorff, locally compact groupoids. Our approach stresses the bundle approach, concrete imprimitivity bimodules and is a preamble to a detailed treatment ... More
On the Cyclically Fully Commutative Elements of Coxeter GroupsFeb 29 2012Let W be an arbitrary Coxeter group. If two elements have expressions that are cyclic shifts of each other (as words), then they are conjugate (as group elements) in W. We say that w is "cyclically fully commutative" (CFC) if every cyclic shift of any ... More
Noise-aided Logic in an Electronic Analog of Synthetic Genetic NetworksDec 14 2012Aug 20 2013We report the experimental verification of noise-enhanced logic behaviour in an electronic analog of a synthetic genetic network, composed of two repressors and two constitutive promoters. We observe good agreement between circuit measurements and numerical ... More
Atari-HEAD: Atari Human Eye-Tracking and Demonstration DatasetMar 15 2019We introduce a large-scale dataset of human actions and eye movements while playing Atari videos games. The dataset currently has 44 hours of gameplay data from 16 games and a total of 2.97 million demonstrated actions. Human subjects played games in ... More
Learning and Verifying Quantified Boolean Queries by ExampleApr 16 2013To help a user specify and verify quantified queries --- a class of database queries known to be very challenging for all but the most expert users --- one can question the user on whether certain data objects are answers or non-answers to her intended ... More
A Stochastic Approach to Shortcut Bridging in Programmable MatterSep 07 2017Sep 18 2018In a self-organizing particle system, an abstraction of programmable matter, simple computational elements called particles with limited memory and communication self-organize to solve system-wide problems of movement, coordination, and configuration. ... More
Finding Cycles and Trees in Sublinear TimeJul 23 2010Apr 03 2012We present sublinear-time (randomized) algorithms for finding simple cycles of length at least $k\geq 3$ and tree-minors in bounded-degree graphs. The complexity of these algorithms is related to the distance of the graph from being $C_k$-minor-free (resp., ... More
Fell bundles and imprimitivity theorems: towards a universal generalized fixed point algebraJun 28 2012Nov 29 2012We apply the One-Sided Action Theorem from the first paper in this series to prove that Rieffel's Morita equivalence between the reduced crossed product by a proper saturated action and the generalized fixed-point algebra is a quotient of a Morita equivalence ... More
Fell bundles and imprimitivity theoremsJan 24 2012Jun 25 2012Our goal in this paper and two sequels is to apply the Yamagami-Muhly-Williams equivalence theorem for Fell bundles over groupoids to recover and extend all known imprimitivity theorems involving groups. Here we extend Raeburn's symmetric imprimitivity ... More
Coactions and Fell bundlesSep 17 2009We show that if $\AA$ is a Fell bundle over a locally compact group $G$, then there is a natural coaction $\delta$ of $G$ on the Fell-bundle $C^*$-algebra $C^*(G,\AA)$ such that if $\hat{\delta}$ is the dual action of $G$ on the crossed product $C^*(G,\AA) ... More
Naturality of Rieffel's Morita equivalence for proper actionsOct 15 2008Suppose that a locally compact group $G$ acts freely and properly on the right of a locally compact space $T$. Rieffel proved that if $\alpha$ is an action of $G$ on a $C^*$-algebra $A$ and there is an equivariant embedding of $C_0(T)$ in $M(A)$, then ... More
Using Game Theory to Study the Evolution of Cultural NormsJun 06 2016Mar 16 2017We discuss how to use evolutionary game theory (EGT) as a framework for studying how cultural dynamics and structural properties can influence the evolution of norms and behaviors within a society. We provide a brief tutorial on how EGT works, and discuss ... More
Fell bundles and imprimitivity theorems: Mansfield's and Fell's theoremsJul 25 2012Mar 19 2013In the third and latest paper in this series, we recover the imprimitivity theorems of Mansfield and Fell using our technique of Fell bundles over groupoids. Also, we apply the Rieffel Surjection of the first paper in the series to relate our version ... More
Fixed-point algebras for proper actions and crossed products by homogeneous spacesJul 03 2009We consider a fixed free and proper action of a locally compact group $G$ on a space $T$, and actions $\alpha:G\to \Aut A$ on $C^*$-algebras for which there is an equivariant embedding of $(C_0(T),\rt)$ in $(M(A),\alpha)$. A recent theorem of Rieffel ... More
Synchronization in counter-rotating oscillatorsJun 28 2011An oscillatory system can have clockwise and anticlockwise senses of rotation. We propose a general rule how to obtain counter-rotating oscillators from the definition of a dynamical system and then investigate synchronization. A type of mixed synchronization ... More
Statistical measures and diffusion dynamics in a modified Chua's circuit equation with multi-scroll attractorsMay 18 2011In this paper the focus is set on a modified Chua's circuit model equation with saw-tooth function in place of piece-wise linear function of Chua's circuit displaying multi-scroll chaotic attractors. We study the characteristic properties of first passage ... More
Induction in stages for crossed products of C*-algebras by maximal coactionsFeb 10 2006Apr 03 2007Let B be a C*-algebra with a maximal coaction of a locally compact group G, and let N and H be closed normal subgroups of G with N contained in H. We show that the process Ind_(G/H)^G which uses Mansfield's bimodule to induce representations of the crossed ... More
Understanding Norm Change: An Evolutionary Game-Theoretic Approach (Extended Version)Apr 16 2017Human societies around the world interact with each other by developing and maintaining social norms, and it is critically important to understand how such norms emerge and change. In this work, we define an evolutionary game-theoretic model to study ... More
Learning Module NetworksOct 19 2012Methods for learning Bayesian network structure can discover dependency structure between observed variables, and have been shown to be useful in many applications. However, in domains that involve a large number of variables, the space of possible network ... More
Context-Free Transductions with Neural StacksSep 08 2018This paper analyzes the behavior of stack-augmented recurrent neural network (RNN) models. Due to the architectural similarity between stack RNNs and pushdown transducers, we train stack RNN models on a number of tasks, including string reversal, context-free ... More
Low Complexity Beamforming Training Method for mmWave CommunicationsMar 16 2017This paper introduces a low complexity method for antenna sector selection in mmWave Hybrid MIMO communication systems like the IEEE 802.11ay amendment for Wireless LANs. The method is backwards compatible to the methods already defined for the released ... More
Non-Malleable Codes for Small-Depth CircuitsFeb 21 2018We construct efficient, unconditional non-malleable codes that are secure against tampering functions computed by small-depth circuits. For constant-depth circuits of polynomial size (i.e. $\mathsf{AC^0}$ tampering functions), our codes have codeword ... More
Detecting falls with X-Factor HMMs when the training data for falls is not availableApr 08 2015Jun 30 2016Identification of falls while performing normal activities of daily living (ADL) is important to ensure personal safety and well-being. However, falling is a short term activity that occurs infrequently. This poses a challenge to traditional classification ... More
Extension problems for representations of crossed-product C*-algebrasFeb 08 2005Nov 09 2006We consider the following problem. Suppose $\alpha$ is an action of a locally compact group $G$ on a $C^*$-algebra $A$, $H$ is a closed subgroup of $G$, and $(\pi,U)$ is a covariant representation of $(A,H,\alpha)$. For which closed subgroups $K$ containing ... More
Tipping Points for Norm Change in Human CulturesApr 19 2018Jul 02 2018Humans interact with each other on a daily basis by developing and maintaining various social norms and it is critical to form a deeper understanding of how such norms develop, how they change, and how fast they change. In this work, we develop an evolutionary ... More
Naturality of Symmetric Imprimitivity TheoremsMar 21 2011May 30 2011The first imprimitivity theorems identified the representations of groups or dynamical systems which are induced from representations of a subgroup. Symmetric imprimitivity theorems identify pairs of crossed products by different groups which are Morita ... More
Security Analysis of Deep Neural Networks Operating in the Presence of Cache Side-Channel AttacksOct 08 2018Nov 28 2018Recent work has introduced attacks that extract the architecture information of deep neural networks (DNN), as this knowledge enhances an adversary's capability to conduct black-box attacks against the model. This paper presents the first in-depth security ... More
Experimental Realization of Quantum-Resonance RatchetsJun 06 2007Nov 27 2007Quantum-resonance ratchets associated with the periodically kicked particle are experimentally realized for the first time. This is achieved by using a Bose-Einstein condensate exposed to a pulsed standing light wave and prepared in an initial state differing ... More
Continuous-Trace Groupoid Crossed ProductsJul 11 2002Let $G$ be a second countable, locally compact groupoid with Haar system, and let $\mathcal{A}$ be a bundle of $C^{\ast}$-algebras defined over the unit space of $G$ on which $G$ acts continuously. We determine conditions under which the associated crossed ... More
Staggered-Ladder Quasienergy Spectra for Generic Quasimomentum and Quantum-Dynamical ManifestationsApr 17 2013A new kind of regular quasienergy (Floquet) spectrum is found for the generalized kicked particle under quantum-resonance conditions at generic quasimomentum, a quantity most relevant in atom-optics experimental realizations of kicked-rotor systems. The ... More
Exact Renormalization Scheme for Quantum Anosov MapsDec 21 1999An exact renormalization scheme is introduced for quantum Anosov maps (QAMs) on a torus for general boundary conditions (BCs), whose number is always finite. Given a QAM $\hat{U}$ with $k$ BCs and Planck's constant $\hbar =2\pi /p$ ($p$ integer), its ... More
Quantum Properties of Double Kicked Systems with Classical Translational Invariance in MomentumOct 27 2014Jan 21 2015Double kicked rotors (DKRs) appear to be the simplest nonintegrable Hamiltonian systems featuring classical translational symmetry in phase space (i.e., in angular momentum) for an \emph{infinite} set of values (the rational ones) of a parameter $\eta$. ... More