Improving Image Classification with Location Context

With the widespread availability of cellphones and cameras that have GPS capabilities, it is common for images being uploaded to the Internet today to have GPS coordinates associated with them. In addition to research that tries to predict GPS coordinates from visual features, this also opens up the door to problems that are conditioned on the availability of GPS coordinates. In this work, we tackle the problem of performing image classification with location context, in which we are given the GPS coordinates for images in both the train and test phases. We explore different ways of encoding and extracting features from the GPS coordinates, and show how to naturally incorporate these features into a Convolutional Neural Network (CNN), the current state-of-the-art for most image classification and recognition problems. We also show how it is possible to simultaneously learn the optimal pooling radii for a subset of our features within the CNN framework. To evaluate our model and to help promote research in this area, we identify a set of location-sensitive concepts and annotate a subset of the Yahoo Flickr Creative Commons 100M dataset that has GPS coordinates with these concepts, which we make publicly available. By leveraging location context, we are able to achieve almost a 7% gain in mean average precision

A Universal Constraint on the Infrared Behavior of the Ghost Propagator in QCD

With proposing a unified description of the fields variation at the level of generating functional, we obtain a new identity for the quark-gluon interaction vertex based on gauge symmetry, which is similar to the Slavnov-Taylor Identities(STIs) based on the Becchi-Rouet-Stora-Tyutin transformation. With these identities, we find that in Landau gauge, the dressing function of the ghost propagator approaches to a constant as its momentum goes to zero, which provides a strong constraint on the infrared behaviour of ghost propagator.Comment: 4 pages, no figur

A three-loop radiative neutrino mass model with dark matter

We present a model that generates small neutrino masses at three-loop level due to the existence of Majorana fermionic dark matter, which is stabilized by a Z2 symmetry. The model predicts that the lightest neutrino is massless. We show a prototypical parameter choice allowed by relevant experimental data, which favors the case of normal neutrino mass spectrum and the dark matter with m \sim 50-135 GeV and a sizable Yukawa coupling. It means that new particles can be searched for in future e+e- collisions.Comment: 7 pages, 3 figure

Neutron scattering study on R2PdSi3 (R = Ho, Er, Tm) compounds

Previous studies on the family of inter-metallic rare-earth compounds R2PdSi3 revealed multifaceted magnetic properties, for instance, spin-glass like behavior. Experimental observations include: Signs of a crystallographic superstructure, complicated magnetic structures both in zero field and in applied magnetic fields as well as a generic phase in applied fields for compounds in the series with the heavy rare-earths R = Gd, Tb, Dy, Ho, Er and Tm. This thesis expands the studies on the magnetic properties of R2PdSi3 employing mainly neutron scattering on single crystals with the focus on the compounds with R = Ho, Er and Tm. A detailed analysis of the crystallographic superstructure using modulation wave approach and group theory is presented. The resulting structure implies the existence of two different rare-earth sites with reduced symmetry and an arrangement of the different sites according to sequences as determined by the superstructure. It will be shown that the reduced symmetry of the rare-earth sites is explicitly observed in the energy spectra of inelastic neutron scattering. The results on the magnetic structures and excitations are shown and discussed in the framework of the superstructure model. Specifically the generic phase in applied fields is interpreted as a direct consequence of the crystallographic superstructure. It is rather unusual that a crystallographic superstructure is playing such a decisive, and through the field dependence also tunable role in determining the magnetic properties as observed in R2PdSi3. The mediating interactions between the crystallographic part and the magnetic part of the system will be discussed.Frühere Untersuchungen der Familie der intermetallischen Selten-Erd Verbindungen R2PdSi3 zeigten vielfältige magnetische Eigenschaften, zum Beispiel ein Spin-glas ähnliches Verhalten. Die experimentellen Beobachtungen beinhalten: Zeichen für eine kristallographische Überstruktur, komplizierte magnetische Strukturen, sowohl im Nullfeld als auch in angelegten Magnetfeldern und darüberhinaus eine generische Phase in Magnetfeldern in den untersuchten Verbindungen mit den schweren Selten-Erden R = Gd, Tb, Dy, Ho, Er und Tm. Diese Dissertation erweitert die Untersuchungen der magnetischen Eigenschaften von R2PdSi3, hauptsächlich durch Verwendung von Neutronenstreuung an Einkristallen, mit dem Schwerpunkt auf den Verbindungen mit R = Ho, Er und Tm. Eine genaue Analyse der kristallographischen Überstruktur mittels Modulationswellenansatz und Gruppentheorie wird präsentiert. Das resultierende Strukturmodell impliziert die Existenz zweier unterschiedlicher Selten-Erd Lagen mit reduzierter Symmetrie in einer Anordnung entsprechend der durch die Überstruktur festgelegten Sequenzen. Es wird gezeigt, dass die reduzierte Symmetrie der Selten-Erd Lagen durch Beobachtungen der inelastischen Neutronenstreuung explizit bestätigt wird. Die Ergebnisse der magnetischen Strukturen und Anregungen werden im Rahmen des Überstrukturmodels diskutiert. Speziell die generische Phase folgt als direkte Konsequenz aus der Überstruktur. Es ist eher ungewöhnlich, dass eine kristallographische Überstruktur eine solch bestimmende und bei Magnetfeldvariation auch “tunebare” Rolle spielt, wie dies in den R2 PdSi3 Verbindungen beobachtet wird. Die vermittelnden Wechselwirkungen zwischen Struktur und Magnetismus werden diskutiert

Integrating Diverse Methodologies and Strategies for the Total Synthesis of Certain Alkaloids and Terpenoids

The body of this thesis is comprised of five scientific articles and is preceded by an overview that contextualizes all of this published/submitted/to be submitted work. The first major part of this thesis is comprised of publication 1. This is a review concerned with the application of Raney-cobalt in organic synthesis. The author's work described in publications 2 and 3 featured Raney-cobalt mediated reductive cyclization reactions as key steps in the construction of the framework of various uleine alkaloids and certain of these are highlighted in this review. Publication 2 comprises the second major part of this thesis. This article details the total syntheses of some key members of uleine alkaloid family (specifically uleine, noruleine, dasycarpidone, nordasycarpidone) by using, as key steps, a palladium-catalysed Ullmann cross-coupling reaction to generate key coupling product and the immediate reductive cyclization of this so as to assemble the uleine alkaloid framework. The third major part of this thesis is comprised of publication 3. This article describes the total synthesis of uleine alkaloid gilbertine. The key intermediate embodying the framework of uleine-type alkaloids was assembled by the Raney-cobalt mediated reductive cyclization of an nitrile compound which was itself constructed via a reaction sequence including a palladium-catalysed Ullmann cross-coupling process. The end-game associated with the synthesis involved a cationic (and possibly biomimetic) cyclisation reaction that established the final, tetrahydropyran ring of gilbertine. The fourth major part of this thesis is comprised of publication 4. This details the total synthesis of a marine-derived sesquiterpene (+)-viridianol. The target molecule was derived from a key intermediate cyclobutone through various functional group manipulations. This cyclobutone was prepared through a photochemically-promoted 1,3-acyl migration reaction involving the cyclopentannulated bicyclo[2.2.2]-octenone, itself constructed from the homochiral compound cis-1,2-dihydrocatechol using Negishi cross-coupling and intramolecular Diels-Alder (IMDA) cycloaddition reactions as key steps. The starting material, a cis-1,2-dihydrocatechol, was obtained through the whole-cell biotransformation of p-iodotoluene using a genetically engineered micro-organism over-expressing the enzyme toluene dioxygenase. The fifth major part of this thesis is comprised of publication 5. This article details a model study relevant to the total synthesis of the marine-derived sesquiterpene (+)-viridianol. Specifically, two structurally related ring-fused cyclopropanes were subjected to the same hydrogenolytic conditions. However, they showed dramatically divergent behavior