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Results for "Conner Chyung"

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Extracting Interpretable Concept-Based Decision Trees from CNNsJun 11 2019Jun 16 2019In an attempt to gather a deeper understanding of how convolutional neural networks (CNNs) reason about human-understandable concepts, we present a method to infer labeled concept data from hidden layer activations and interpret the concepts through a ... More
Extracting Interpretable Concept-Based Decision Trees from CNNsJun 11 2019In an attempt to gather a deeper understanding of how convolutional neural networks (CNNs) reason about human-understandable concepts, we present a method to infer labeled concept data from hidden layer activations and interpret the concepts through a ... More
A rank 18 Waring decomposition of $sM_{\langle 3\rangle}$ with 432 symmetriesNov 15 2017The recent discovery that the exponent of matrix multiplication is determined by the rank of the symmetrized matrix multiplication tensor has invigorated interest in better understanding symmetrized matrix multiplication. I present an explicit rank 18 ... More
Inverse Limits of Finite Rank Free GroupsMay 02 2011Aug 03 2011We will show that all inverse limits of finite rank free groups index by the natural numbers are isomorphic either to a finite rank free group or to a fixed universal group. In other words, any inverse system of finite rank free groups which is not equivalent ... More
Commensurated subgroups, semistability and simple connectivity at infinityJan 13 2012A subgroup Q is commensurated in a group G if each G conjugate of Q intersects Q in a group that has finite index in both Q and the conjugate. So commensurated subgroups are similar to normal subgroups. Semistability and simple connectivity at infinity ... More
$A_{\infty}$-algebra Structures Associated to $\mathcal{K}_2$-algebrasMay 27 2010Jun 14 2010The notion of a $\mathcal{K}_2$-algebra was recently introduced by Cassidy and Shelton as a generalization of the notion of a Koszul algebra. The Yoneda algebra of any connected graded algebra admits a canonical $A_{\infty}$-algebra structure. This structure ... More
$\mathcal K_2$ factors of Koszul algebras and applications to face ringsSep 23 2011Generalizing the notion of a Koszul algebra, a graded k-algebra A is K2 if its Yoneda algebra is generated as an algebra in cohomology degrees 1 and 2. We prove a strong theorem about K2 factor algebras of Koszul algebras and use that theorem to show ... More
Some non-Koszul algebras from rational homotopy theoryJul 17 2014Feb 17 2015The McCool group, denoted $P\Sigma_n$, is the group of pure symmetric automorphisms of a free group of rank $n$. The cohomology algebra $H^*(P\Sigma_n, \mathbb{Q})$ was determined by Jensen, McCammond and Meier. We prove that $H^*(P\Sigma_n, \mathbb{Q})$ ... More
From Twisted Quantum Loop Algebras to Twisted YangiansMay 14 2015We prove how the Yangian of $\mathfrak{gl}_N$ in its RTT presentation and Olshanski's twisted Yangians for the orthogonal and symplectic Lie algebras can be obtained by a degeneration process from the corresponding quantum loop algebra and some of its ... More
Concerning Fundamental Groups of Locally Connected Subsets of the PlaneMay 02 2011May 17 2013We show that every homomorphism from a one-dimensional Peano continuum to a planar Peano continuum is induced by a continuous map up to conjugation. We then prove that the topological structure of the space of points at which a planar Peano continuum ... More
Local topological properties of asymptotic cones of groupsOct 16 2012We define a local analogue to Gromov's loop division property which is use to give a sufficient condition for an asymptotic cone of a complete geodesic metric space to have uncountable fundamental group. As well, this property is used to understand the ... More
Classification, Koszulity and Artin-Schelter Regularity of some Graded Twisted Tensor ProductsNov 25 2018Let $\mathbb{k}$ be an algebraically closed field. We classify all of the quadratic twisted tensor products $A \otimes_{\tau} B$ in the cases where $(A, B) = (\mathbb{k}[x], \mathbb{k}[y])$ and $(A, B) = (\mathbb{k}[x, y], \mathbb{k}[z])$. We determine ... More
The Koszul Property for Graded Twisted Tensor ProductsAug 08 2017Jun 04 2018Let $k$ be a field. Let $A$ and $B$ be connected $N$-graded $k$-algebras. Let $C$ denote a twisted tensor product of $A$ and $B$ in the category of connected $N$-graded $k$-algebras. The purpose of this paper is to understand when $C$ possesses the Koszul ... More
Ends of iterated function systemsMar 06 2014Guided by classical concepts, we define the notion of \emph{ends} of an iterated function system and prove that the number of ends is an upper bound for the number of nondegenerate components of its attractor. The remaining isolated points are then linked ... More
A note on automatic continuityOct 13 2017We present new results regarding automatic continuity, unifying some diagonalization concepts that have been developed over the years. For example, any homomorphism from a completely metrizable topological group to Thompson's group $F$ has open kernel. ... More
Towards Controlling Refinements of StatechartsMar 25 2015In incremental development strategies, modelers frequently refine Statecharts models to satisfy requirements and changes. Although several solutions exist to the problem of Statecharts refinement, they provide such levels of freedom that a statechart ... More
The homotopy dimension of codiscrete subsets of the 2-sphereMar 03 2006We characterize those planar Peano continua that are homotopy equivalent to 1-dimensional sets. While many planar Peano continua are not homotopically 1-dimensional, we prove that each has fundamental group that embeds in the fundamental group of a 1-dimensional ... More
Some anomalous examples of lifting spacesAug 02 2017An inverse limit of a sequence of covering spaces over a given space $X$ is not, in general, a covering space over $X$ but is still a lifting space, i.e. a Hurewicz fibration with unique path lifting property. Of particular interest are inverse limits ... More
Self-affine ManifoldsFeb 12 2014Nov 09 2015This paper studies closed 3-manifolds which are the attractors of a system of finitely many affine contractions that tile $\mathbb{R}^3$. Such attractors are called self-affine tiles. Effective characterization and recognition theorems for these 3-manifolds ... More
Commensurators and Quasi-Normal SubgroupsDec 29 2009We say A is a quasi-normal subgroup of the group G if the commensurator of A in G is all of G. We develop geometric versions of commensurators in finitely generated groups. In particular, g is an element of the commensurator of A in G iff the Hausdorff ... More
Archipelago groupsOct 30 2014The classical archipelago is a non-contractible subset of $\mathbb{R}^3$ which is homeomorphic to a disk except at one non-manifold point. Its fundamental group, $\mathcal{A}$, is the quotient of the topologist's product of $\mathbb Z$, the fundamental ... More
Deep Convolutional Neural Networks for Noise Detection in ECGsOct 05 2018Mobile electrocardiogram (ECG) recording technologies represent a promising tool to fight the ongoing epidemic of cardiovascular diseases, which are responsible for more deaths globally than any other cause. While the ability to monitor one's heart activity ... More
On the First Homology of Peano ContinuaSep 23 2015We show that the first homology group of a locally connected compact metric space is either uncountable or is finitely generated. This is related to Shelah's well-known result which shows that the fundamental group of such a space satisfies a similar ... More
Geometry of compact lifting spacesJan 07 2019We study a natural generalization of inverse systems of finite regular covering spaces. A limit of such a system is a fibration whose fibres are profinite topological groups. However, as shown in a previous paper (Conner-Herfort-Pavesic: Some anomalous ... More
Noncommutative Knörrer periodicity and noncommutative Kleinian singularitiesSep 18 2018We establish a version of Kn\"{o}rrer's Periodicity Theorem in the context of noncommutative invariant theory. Namely, let $A$ be a left noetherian AS-regular algebra, let $f$ be a normal and regular element of $A$ of positive degree, and take $B=A/(f)$. ... More
Monte Carlo simulation of a very high resolution thermal neutron detector composed of glass scintillator microfibersJun 11 2016In order to develop a high spatial resolution (micron level) thermal neutron detector, a detector assembly composed of cerium doped lithium glass microfibers, each with a diameter of 1\,$\mu$m, is proposed, where the neutron absorption location is reconstructed ... More
Noncommutative Knörrer periodicity and noncommutative Kleinian singularitiesSep 18 2018Feb 25 2019We establish a version of Kn\"{o}rrer's Periodicity Theorem in the context of noncommutative invariant theory. Namely, let $A$ be a left noetherian AS-regular algebra, let $f$ be a normal and regular element of $A$ of positive degree, and take $B=A/(f)$. ... More
Periodic free resolutions from twisted matrix factorizationsJul 31 2013The notion of a matrix factorization was introduced by Eisenbud in the commutative case in his study of bounded (periodic) free resolutions over complete intersections. In this work, we extend the notion of (homogeneous) matrix factorizations to regular ... More
On small homotopies of loopsDec 11 2007Two natural questions are answered in the negative: (1) If a space has the property that small nulhomotopic loops bound small nulhomotopies, then are loops which are limits of nulhomotopic loops themselves nulhomotopic? (2) Can adding arcs to a space ... More
Finiteness conditions on the Yoneda algebra of a monomial algebraOct 11 2012Let A be a connected graded noncommutative monomial algebra. We associate to A a finite graph \Gamma(A) called the CPS graph of A. Finiteness properties of the Yoneda algebra Ext_A(k,k) including Noetherianity, finite GK dimension, and finite generation ... More
Eliciting the Endowment Effect under Assigned OwnershipSep 22 2018Oct 04 2018In this study we present evidence that endowment effect can be elicited merely by assigned ownership. Using Google Customer Survey, we administered a survey were participants (n=495) were randomly split into 4 groups. Each group was assigned ownership ... More
The Geometry and Fundamental Groups of Solenoid ComplementsDec 01 2012When a solenoid is embedded in three space, its complement is an open three manifold. We discuss the geometry and fundamental groups of such manifolds, and show that the complements of different solenoids (arising from different inverse limits) have different ... More
A geometric study of Strassen's asymptotic rank conjecture and its variantsNov 13 2018We establish basic information about the set of tight tensors, the tensors with continuous regular symmetry. Our motivation is Strassen's astounding asymptotic rank conjecture that the asymptotic rank of any tight tensor is minimal. In particular, we ... More
Itinerant Antiferromagnetism in FeMnP0.8Si0.2 Single CrystalsJul 01 2015Compounds based on the Fe2P structure have continued to attract interest because of the interplay between itinerant and localized magnetism in a non-centrosymmetric crystal structure, and because of the recent developments of these materials for magnetocaloric ... More
Energy Harvesting with a Liquid-Metal Microfluidic Influence MachineMar 06 2018We describe and demonstrate a new energy harvesting technology based on a microfluidic realization of a Wimshurst influence machine. The prototype device converts the mechanical energy of a pressure-driven flow into electrical energy, using a multiphase ... More
Evidence for a pulsar wind nebula in the Type Ib-peculiar supernova SN 2012auSep 04 2018We present an optical spectrum of the energetic Type Ib supernova (SN) 2012au obtained at an unprecedented epoch of 6.2 years after explosion. Forbidden transition emission lines of oxygen and sulfur are detected with expansion velocities of 2300 km/s. ... More
Ring-Like Structure in the Radio Lobe of MG0248+0641Aug 16 1997Oct 01 1997We present radio and optical observations of MG0248+0641, which contains a kiloparsec-scale ring-like structure in one of its radio lobes. The radio observations show a typical core-double morphology: a central core between two lobes, each of which has ... More
Search for domain wall dark matter with atomic clocks on board global positioning system satellitesApr 22 2017Oct 30 2017Cosmological observations indicate that 85% of all matter in the Universe is dark matter (DM), yet its microscopic composition remains a mystery. One hypothesis is that DM arises from ultralight quantum fields that form macroscopic objects such as topological ... More
Novel approaches to dark-matter detection using space-time separated clocksFeb 19 2019We discuss the theoretical analysis and interpretation of space-time separated clock experiments in the context of a space-time varying scalar field that is non-universally coupled to the standard model fields. If massive, such a field is a candidate ... More
Low Surface Brightness Radio Structure in the Field of Gravitational Lens 0957+561Aug 19 1997We have produced deep radio maps of the double quasar 0957+561 from multiple-epoch VLA observations. To achieve high sensitivity to extended structure we have re-reduced the best available 1.6 GHz observations and have combined 5 GHz data from multiple ... More
Vortex lock-in transition and evidence for transitions among commensurate kinked vortex configurations in single-layered Fe arsenidesMar 12 2013We report an angle-dependent study of the magnetic torque $\tau(\theta)$ within the vortex state of single-crystalline LaO$_{0.9}$F$_{0.1}$FeAs and SmO$_{0.9}$F$_{0.1}$FeAs as a function of both temperature $T$ and magnetic field $H$. Sharp peaks are ... More
Measurement of neutron capture on $^{136}$XeMay 19 2016Sep 29 2016$^{136}$Xe is a 0{\nu}{\beta}{\beta} decay candidate isotope, and is used in multiple experiments searching for this hypothetical decay mode. These experiments require precise information about neutron capture for their background characterization and ... More
Disorder-dependent superconducting phase-diagram at high magnetic fields in Fe$_{1 + y}$Se$_{x}$Te$_{1-x}$ ($x \sim 0.4$)Jun 14 2011Nov 04 2011We compare the superconducting phase-diagram under high magnetic fields (up to $H = 45$ T) of Fe$_{1+y}$Se$_{0.4}$Te$_{0.6}$ single crystals originally grown by the Bridgman-Stockbarger (BRST) technique, which were annealed to display narrow superconducting ... More
Magnetic order in quasi-two-dimensional molecular magnets investigated with muon-spin relaxationApr 18 2011Aug 25 2011We present the results of a muon-spin relaxation (muSR) investigation into magnetic ordering in several families of layered quasi-two-dimensional molecular antiferromagnets based on transition metal ions such as S=1/2 Cu2+ bridged with organic ligands ... More
The Gravitationally-Lensed Radio Source MG0751+2716Feb 21 1997May 15 1997We report the discovery of a new gravitationally lensed radio source. Radio maps of MG0751+2716 show four lensed images, which, at higher resolution, are resolved into long arcs of emission. A group of galaxies is present in optical images, including ... More
Muon-fluorine entangled states in molecular magnetsJul 18 2007The information accessible from a muon-spin relaxation experiment is often limited since we lack knowledge of the precise muon stopping site. We demonstrate here the possibility of localizing a spin polarized muon in a known stopping state in a molecular ... More
Fermi-surface of underdoped LaFeAsO1-xFx as determined by the Haas-van Alphen-effectSep 07 2010Here, we present a de Haas-van Alphen (dHvA) effect1 study on the newly discovered LaFeAsO1-xFx compounds2,3 in order to unveil the topography of the Fermi surface associated with their antiferromagnetic and superconducting phases, which is essential ... More
Growth and Characterization of Ce- Substituted Nd2Fe14B Single CrystalsAug 31 2015Single crystals of (Nd1-xCex)2Fe14B are grown out of Fe-(Nd,Ce) flux. Chemical and structural analysis of the crystals indicates that (Nd1-xCex)2Fe14B forms a solid solution until at least x = 0.38 with a Vegard-like variation of the lattice constants ... More
Unidirectional Distributed Acoustic Reflection Transducers for Quantum ApplicationsMay 08 2019Recent significant advances in coupling superconducting qubits to acoustic wave resonators has led to demonstrations of quantum control of surface and bulk acoustic resonant modes as well Wigner tomography of quantum states in these modes. These advances ... More
Violating Bell's inequality with remotely-connected superconducting qubitsAug 09 2018Oct 17 2018Quantum communication relies on the efficient generation of entanglement between remote quantum nodes, due to entanglement's key role in achieving and verifying secure communications. Remote entanglement has been realized using a number of different probabilistic ... More
Phonon-mediated quantum state transfer and remote qubit entanglementMar 13 2019Phonons, and in particular surface acoustic wave phonons, have been proposed as a means to coherently couple distant solid-state quantum systems. Recent experiments have shown that superconducting qubits can control and detect individual phonons in a ... More
Evidence for negative thermal expansion in the superconducting precursor phase SmFeAsOFeb 23 2018The fluorine-doped rare-earth iron oxypnictide series SmFeAsO$_{1-x}$F$_x$ (0 $\leq x \leq$ 0.10) was investigated with high resolution powder x-ray scattering. In agreement with previous studies, the parent compound SmFeAsO exhibits a tetragonal-to-orthorhombic ... More
Performance of the STACEE Atmospheric Cherenkov TelescopeOct 17 2000The Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE) is located at the National Solar Thermal Test Facility of Sandia National Laboratories in Albuquerque, New Mexico, USA. The field of solar tracking mirrors (heliostats) around a central ... More
Control of the third dimension in copper-based square-lattice antiferromagnetsMar 01 2016Using a mixed-ligand synthetic scheme, we create a family of quasi-two-dimensional antiferromagnets, namely, [Cu(HF$_2$)(pyz)$_2$]ClO$_4$ [pyz = pyrazine], [Cu$L_2$(pyz)$_2$](ClO$_4$)$_2$ [$L$ = pyO = pyridine-N-oxide and 4-phpyO = 4-phenylpyridine-N-oxide. ... More
Magnetic order in the S=1/2 two-dimensional molecular antiferromagnet, copper pyrazine perchlorate Cu(Pz)_2(ClO_4)_2Dec 13 2006We present an investigation of magnetic ordering in the two-dimensional S=1/2 quantum magnet Cu(Pz)_2(ClO_4)_2 using specific heat and zero field muon-spin relaxation (\mu^+SR). The magnetic contribution to the specific heat is consistent with an exchange ... More
Quantum control of surface acoustic wave phononsApr 19 2018The superposition of quantum states is one of the hallmarks of quantum physics, and clear demonstrations of superposition have been achieved in a number of quantum systems. However, mechanical systems have remained a challenge, with only indirect demonstrations ... More
Design of an Autonomous Precision Pollination RobotAug 29 2018Precision robotic pollination systems can not only fill the gap of declining natural pollinators, but can also surpass them in efficiency and uniformity, helping to feed the fast-growing human population on Earth. This paper presents the design and ongoing ... More
The STACEE-32 Ground Based Gamma-ray DetectorMay 29 2002We describe the design and performance of the Solar Tower Atmospheric Cherenkov Effect Experiment detector in its initial configuration (STACEE-32). STACEE is a new ground-based gamma ray detector using the atmospheric Cherenkov technique. In STACEE, ... More
High Energy Gamma-Ray Observations of the Crab Nebula and Pulsar with the Solar Tower Atmospheric Cherenkov Effect ExperimentJun 21 2000The Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE) is a new ground-based atmospheric Cherenkov telescope for gamma-ray astronomy. STACEE uses the large mirror area of a solar heliostat facility to achieve a low energy threshold. A prototype ... More
First dark matter search results from a 4-kg CF$_3$I bubble chamber operated in a deep underground siteApr 13 2012Sep 19 2012New data are reported from the operation of a 4.0 kg CF$_{3}$I bubble chamber in the 6800-foot-deep SNOLAB underground laboratory. The effectiveness of ultrasound analysis in discriminating alpha-decay background events from single nuclear recoils has ... More
The Type II-Plateau Supernova 2017eaw in NGC 6946 and Its Red Supergiant ProgenitorMar 09 2019We present extensive optical photometric and spectroscopic observations, from 4 to 482 days after explosion, of the Type II-plateau (II-P) supernova (SN) 2017eaw in NGC 6946. SN 2017eaw is a normal SN II-P intermediate in properties between, for example, ... More
The Type II-Plateau Supernova 2017eaw in NGC 6946 and Its Red Supergiant ProgenitorMar 09 2019Apr 18 2019We present extensive optical photometric and spectroscopic observations, from 4 to 482 days after explosion, of the Type II-plateau (II-P) supernova (SN) 2017eaw in NGC 6946. SN 2017eaw is a normal SN II-P intermediate in properties between, for example, ... More
Transverse momentum spectra of charged particles in proton-proton collisions at $\sqrt{s} = 900$~GeV with ALICE at the LHCJul 05 2010Aug 19 2010The inclusive charged particle transverse momentum distribution is measured in proton-proton collisions at $\sqrt{s} = 900$~GeV at the LHC using the ALICE detector. The measurement is performed in the central pseudorapidity region $(|\eta|<0.8)$ over ... More
Midrapidity antiproton-to-proton ratio in pp collisions at $\sqrt{s} = 0.9$ and $7$~TeV measured by the ALICE experimentJun 28 2010The ratio of the yields of antiprotons to protons in pp collisions has been measured by the ALICE experiment at $\sqrt{s} = 0.9$ and $7$~TeV during the initial running periods of the Large Hadron Collider(LHC). The measurement covers the transverse momentum ... More
First proton--proton collisions at the LHC as observed with the ALICE detector: measurement of the charged particle pseudorapidity density at sqrt(s) = 900 GeVNov 28 2009Dec 01 2009On 23rd November 2009, during the early commissioning of the CERN Large Hadron Collider (LHC), two counter-rotating proton bunches were circulated for the first time concurrently in the machine, at the LHC injection energy of 450 GeV per beam. Although ... More
Charged-particle multiplicity measurement in proton-proton collisions at sqrt(s) = 0.9 and 2.36 TeV with ALICE at LHCApr 18 2010May 06 2010Charged-particle production was studied in proton-proton collisions collected at the LHC with the ALICE detector at centre-of-mass energies 0.9 TeV and 2.36 TeV in the pseudorapidity range |eta| < 1.4. In the central region (|eta| < 0.5), at 0.9 TeV, ... More
Two-pion Bose-Einstein correlations in pp collisions at sqrt(s)=900 GeVJul 03 2010We report on the measurement of two-pion correlation functions from pp collisions at sqrt(s)=900 GeV performed by the ALICE experiment at the Large Hadron Collider. Our analysis shows an increase of the HBT radius with increasing event multiplicity, in ... More
Charged-particle multiplicity measurement in proton-proton collisions at sqrt(s) = 7 TeV with ALICE at LHCApr 20 2010May 21 2010The pseudorapidity density and multiplicity distribution of charged particles produced in proton-proton collisions at the LHC, at a centre-of-mass energy sqrt(s) = 7 TeV, were measured in the central pseudorapidity region |eta| < 1. Comparisons are made ... More