9,395 research outputs found
3D Character Modeling in Virtual Reality
The paper presents a virtual reality modeling system based on interactive web technologies. The system's goal is to provide a user-friendly virtual environment for the development of 3D characters with an articulated structure. The interface allows the modeling of both the character's joint structure (the hierarchy) and its segment geometry (the skin). The novelty of the system consists of (1) the combination of web technologies used (VRML, Java and EAI) which provides the possibility of online modeling, (2) rules and constraints based operations and thus interface elements, (3) vertices and sets of vertices used as graphics primitives and (4) the possibility to handle and extend hierarchies based on the H-anim structure elements
Characterisation and textural analysis of Middle Bronze Age Transdanubian inlaid wares of the Encrusted Pottery Culture, Hungary: a preliminary study
Inlaid ceramics belonging to the Encrusted Pottery Culture and dated to the Middle Bronze Age (2000–1500 BC) are highly distinctive vessels with complex decorative motifs found in large numbers in the Transdanubia region of Hungary. Despite this considerable corpus of material there has been little systematic investigation of the composition of the inlays. Micro-analysis of Transdanubian inlaid wares by X-ray diffraction (XRD), micro-Fourier transform infrared microscopy (FT-IR), and scanning electron microscopy (SEM) provides new compositional, structural and textural information on the inlays. In contrast to common statements in the literature regarding the materials used to make inlays, these new data show that the majority of inlays are composed of hydroxyapatite (bone) that was previously ashed, although some of the inlays are composed of calcium carbonate. Additional compositional and textural variation in the bone inlays suggests that bone material from different skeletal elements and/or of different age may have been used, and that contrasting recipes for inlay preparation were employed during fabrication. These results suggest that the production of inlaid vessels of the Encrusted Pottery Culture was more complex than has hitherto been thought
Asymmetric fundamental band CO lines as a sign of an embedded giant planet
We investigate the formation of double-peaked asymmetric line profiles of CO
in the fundamental band spectra emitted by young (1-5Myr) protoplanetary disks
hosted by a 0.5-2 Solar mass star. Distortions of the line profiles can be
caused by the gravitational perturbation of an embedded giant planet with q=4.7
10^-3 stellar-to-planet mass ratio. Locally isothermal, 2D hydrodynamic
simulations show that the disk becomes globally eccentric inside the planetary
orbit with stationary ~0.2-0.25 average eccentricity after ~2000 orbital
periods. For orbital distances 1-10 AU, the disk eccentricity is peaked inside
the region where the fundamental band of CO is thermal excitated. Hence, these
lines become a sensitive indicators of the embedded planet via their
asymmetries (both in flux and wavelength). We find that the line shape
distortions (e.g. distance, central dip, asymmetry and positions of peaks) of a
given transition depend on the excitation energy (i.e. on the rotational
quantum number J). The magnitude of line asymmetry is increasing/decreasing
with J if the planet orbits inside/outside the CO excitation zone (R_CO<=3, 5
and 7 AU for a 0.5,1 and 2 Solar mass star, respectively), thus one can
constrain the orbital distance of a giant planet by determining the slope of
peak asymmetry-J profile. We conclude that the presented spectroscopic
phenomenon can be used to test the predictions of planet formation theories by
pushing the age limits for detecting the youngest planetary systems.Comment: 7 pages, 5 figures, to appear in ApJ
Dynamical Equations from a First-Order Perturbative Superspace Formulation of 10D N=1 String-Corrected Supergravity (I)
Utilizing a first-order perturbative superspace approach, we derive the
bosonic equations of motion for the 10D, N = 1 supergravity fields. We give the
Lagrangian corresponding to these equations derived from superspace geometry.
Moreover, the equivalence of this Lagrangian to the first-order perturbative
component level Lagrangian of anomaly-free supergravity is proven. Our
treatment covers both the two-form and six-form formulations.Comment: 20 pages, no figures, references and note in proof adde
Complex chaos in conditional qubit dynamics and purification protocols
Selection of an ensemble of equally prepared quantum systems, based on
measurements on it, is a basic step in quantum state purification. For an
ensemble of single qubits, iterative application of selective dynamics has been
shown to lead to complex chaos, which is a novel form of quantum chaos with
true sensitivity to the initial conditions. The Julia set of initial valuse
with no convergence shows a complicated structre on the complex plane. The
shape of the Julia set varies with the parameter of the dynamics. We present
here results for the two qubit case demonstrating how a purification process
can be destroyed with chaotic oscillations
Complex chaos in the conditional dynamics of qubits
We analyze the consequences of iterative measurement-induced nonlinearity on
the dynamical behavior of qubits. We present a one-qubit scheme where the
equation governing the time evolution is a complex-valued nonlinear map with
one complex parameter. In contrast to the usual notion of quantum chaos,
exponential sensitivity to the initial state occurs here. We calculate
analytically the Lyapunov exponent based on the overlap of quantum states, and
find that it is positive. We present a few illustrative examples of the
emerging dynamics.Comment: 4 pages, 3 figure
Issues in management of artificial intelligence based projects
Now that Artificial Intelligence (AI) is gaining acceptance, it is important to examine some of the obstacles that still stand in the way of its progress. Ironically, many of these obstacles are related to management and are aggravated by the very characteristcs that make AI useful. The purpose of this paper is to heighten awareness of management issues in AI development and to focus attention on their resolution
Dynamics of multi-frequency oscillator ensembles with resonant coupling
We study dynamics of populations of resonantly coupled oscillators having
different frequencies. Starting from the coupled van der Pol equations we
derive the Kuramoto-type phase model for the situation, where the natural
frequencies of two interacting subpopulations are in relation 2:1. Depending on
the parameter of coupling, ensembles can demonstrate fully synchronous
clusters, partial synchrony (only one subpopulation synchronizes), or
asynchrony in both subpopulations. Theoretical description of the dynamics
based on the Watanabe-Strogatz approach is developed.Comment: 12 page
- …