Morphing of Triangular Meshes in Shape Space

We present a novel approach to morph between two isometric poses of the same non-rigid object given as triangular meshes. We model the morphs as linear interpolations in a suitable shape space $\mathcal{S}$. For triangulated 3D polygons, we prove that interpolating linearly in this shape space corresponds to the most isometric morph in $\mathbb{R}^3$. We then extend this shape space to arbitrary triangulations in 3D using a heuristic approach and show the practical use of the approach using experiments. Furthermore, we discuss a modified shape space that is useful for isometric skeleton morphing. All of the newly presented approaches solve the morphing problem without the need to solve a minimization problem.Comment: Improved experimental result

Open-world Learning and Application to Product Classification

Classic supervised learning makes the closed-world assumption, meaning that classes seen in testing must have been seen in training. However, in the dynamic world, new or unseen class examples may appear constantly. A model working in such an environment must be able to reject unseen classes (not seen or used in training). If enough data is collected for the unseen classes, the system should incrementally learn to accept/classify them. This learning paradigm is called open-world learning (OWL). Existing OWL methods all need some form of re-training to accept or include the new classes in the overall model. In this paper, we propose a meta-learning approach to the problem. Its key novelty is that it only needs to train a meta-classifier, which can then continually accept new classes when they have enough labeled data for the meta-classifier to use, and also detect/reject future unseen classes. No re-training of the meta-classifier or a new overall classifier covering all old and new classes is needed. In testing, the method only uses the examples of the seen classes (including the newly added classes) on-the-fly for classification and rejection. Experimental results demonstrate the effectiveness of the new approach.Comment: accepted by The Web Conference (WWW 2019) Previous title: Learning to Accept New Classes without Trainin

Vector analogues of the Maggi-Rubinowicz theory of edge diffraction

The Maggi-Rubinowicz technique for scalar and electromagnetic fields is interpreted as a transformation of an integral over an open surface to a line integral around its rim. Maggi-Rubinowicz analogues are found for several vector physical optics representations. For diffraction from a circular aperture, a numerical comparison between these formulations shows the two methods are in agreement. To circumvent certain convergence difficulties in the Maggi-Rubinowicz integrals that occur as the observer approaches the shadow boundary, a variable mesh integration is used. For the examples considered, where the ratio of the aperture diameter to wavelength is about ten, the Maggi-Rubinowicz formulation yields an 8 to 10 fold decrease in computation time relative to the physical optics formulation

Kaluza-Klein Gluons as a Diagnostic of Warped Models

We study the properties of $g^{1}$, the first excited state of the gluon in representative variants of the Randall Sundrum model with the Standard Model fields in the bulk. We find that measurements of the coupling to light quarks (from the inclusive cross-section for $pp\to g^{1} \to t\bar t$), the coupling to bottom quarks (from the rate of $pp\to g^{1} b$), as well as the overall width, can provide powerful discriminants between the models. In models with large brane kinetic terms, the $g^1$ resonance can even potentially be discovered decaying into dijets against the large QCD background. We also derive bounds based on existing Tevatron searches for resonant $t \bar{t}$ production and find that they require $M_{g^{1}} \gtrsim 950$ GeV. In addition we explore the pattern of interference between the $g^1$ signal and the non-resonant SM background, defining an asymmetry parameter for the invariant mass distribution. The interference probes the relative signs of the couplings of the $g^{1}$ to light quark pairs and to $t\bar t$, and thus provides an indication that the top is localized on the other side of the extra dimension from the light quarks, as is typical in the RS framework.Comment: 25 pages, 10 figure

Outflows driven by Giant Protoplanets

We investigate outflows driven by a giant protoplanet using three-dimensional MHD nested grid simulations. We consider a local region around the protoplanet in the protoplanetary disk, and calculate three models: (a) unmagnetized disk model, (b) magnetized disk model having magnetic field azimuthally parallel to the disk, and (c) magnetic field perpendicular to the disk. Outflows with velocities, at least, 10 km/s are driven by the protoplanets in both magnetized disk models, while outflow does not appear in unmagnetized disk model. Tube-like outflows along the azimuthal direction of the protoplanetary disk appear in model with magnetic field being parallel to the disk. In this model, the magnetically dominated regions (i.e., density gap) are clearly contrasted from other regions and spiral waves appear near the protoplanet. On the other hand, in model with magnetic field being perpendicular to the disk, outflows are driven by a protoplanet with cone-like structure just as seen in the outflow driven by a protostar. Magnetic field lines are strongly twisted near the protoplanet and the outflows have well-collimated structures in this model.These outflows can be landmarks for searching exo-protoplanets in their formation stages. Our results indicate that the accretion rate onto the protoplanet tend to have a larger value than that expected from previous hydrodynamical calculations, since a fraction of the angular momentum of circum-planetary disk is removed by outflows, enhanced non-axisymmetric patterns caused by magnetic field, and magnetic braking. Possible implications for observation are also briefly discussed.Comment: 11 pages, 3 figures, Submitted to ApJL, For high resolution figures see http://www2.scphys.kyoto-u.ac.jp/~machidam/jupiter/doc/resubmit_0703.pd

Absorption Systems In Radio-Selected QSO Surveys

Radio-selected samples of quasars with complete optical identifications offer an ideal dataset with which to investigate dust bias associated with intervening absorption systems. Here, we review our work on the Complete Optical and Radio Absorption Line System (CORALS) survey whose aim is to quantify this bias and assess the impact of dust on absorber statistics. First, we review previously published results on the number density and gas content of high column density absorbers over the redshift range 0.6 < z < 3.5. We then present the latest results from CORALS which focus on measuring the metal content of our unbiased absorber sample and an investigation of their optical--IR colours. Overall we find that although dust is unarguably present in absorption galaxies, the level appears to be low enough that the statistics of previous magnitude limited samples have not been severely affected and that the subsequent reddening of background QSOs is small.Comment: Proceedings of IAUC199, Probing Galaxies through Quasar Absorption Lines, P. R. Williams, C. Shu, and B. Menard, ed

Explorations of the Top Quark Forward-Backward Asymmetry at the Tevatron

We consider the recent measurement of the top quark forward-backward asymmetry at the Fermilab Tevatron, which shows a discrepancy of slightly more than 2$\sigma$ compared to the SM prediction. We find that $t$-channel exchange of a color sextet or triplet scalar particle can explain the measurement, while leaving the cross section for $t \bar{t}$ production within measured uncertainties. Such particles have good discovery prospects by study of the kinematic structure of $t \bar{t}$+jets at the LHC.Comment: 14 pages, 10 figures, 1 tabl