424 research outputs found
\u3cem\u3eJack\u3c/em\u3e/TTES: A System for Production and Real-Time Playback of Human Figure Motion in a DIS Environment
This document describes a modified Jack system for off-line motion production and on-line (real-time) motion playback to an external IRIS-Performer-based host rendering system. This work was done in partial fulfillment of Contract #N61339-94-C-0005 for the US Marine Corps through NAWCTSD (Naval Air Warfare Center, Training Systems Division). The work described herein was contributed by several of the members of the Center for Human Modeling and Simulation: John Granieri (Design/Engineering/Integration), Rama Bindiganavale (animator, posture transitions), Hanns-Oskar Poor (animator, posture transitions, Hyeongseok Ko (walking and running motion), Micheal Hollick (locomotion playback control), Bond-Jay Ting (body sculpting), Francisco Azoula (body sculptin, anthropometry), Pei-Hwa Ho (body normalization), Jonathan Crabtree (Performaer, TIPS file format), Xinmin Zhao (slaving), Zhongyang Feng (DIS logfile player), Welton Becket and Barry Reich (terrain reasoning and reactive agent control)
Production and Playback of Human Figure Motion 3D Virtual Environments
We describe a system for off-line production and real-time playback of motion for articulated human figures in 3D virtual environments. The key notions are (1) the logical storage of full body motion in posture graphs, which provides a simple motion access method for playback, and (2) mapping the motions of higher DOF figures using slaving to provide human models at several levels of detail, both in geometry and articulation, for later playback. We present our system in a context of a simple problem: Animating human figures in a distributed simulation, using DIS protocols for communication the human state information. We also discuss several related techniques for real-time animation of articulated figures in visual simulation
Real-Time Control of a Virtual Human Using Minimal Sensors
We track, in real-time, the position and posture of a human body, using a minimal number of 6 DOF sensors to capture full body standing postures. We use 4 sensors to create a good approximation of a human operator\u27s position and posture, and map it on to our articulated computer graphics human model. The unsensed joints are positioned by a fast inverse kinematics algorithm. Our goal is to realistically recreate human postures while minimally encumbering the operator
Optical bistability in a -type atomic system including near dipole-dipole interaction
The advantage of optical bistability (OB) using three-level
electromagnetically induced transparency (EIT) atomic system over the two-level
system is its controllability, as absorption, dispersion, and optical
nonlinearity in one of the atomic transitions can be modified considerably by
the field interacting with nearby atomic transitions. This is due to induced
atomic coherences generated in such EIT system. The inclusion of near
dipole-dipole (NDD) interaction among atoms further modifies absorption,
dispersion, and optical nonlinearity of three-level EIT system and the OB can
also be controlled by this interaction, producing OB to multistability.Comment: 15 pages, 6 figure
Stability Analysis of the LHC Cables for Transient Heat Depositions
The commissioning and the exploitation of the LHC require a good knowledge of the stability margins of the superconducting magnets with respect to beam induced heat depositions. Previous studies showed that simple numerical models are suitable to carry out stability calculations of multi-strands cables, and highlighted the relevance of the heat transfer model with the surrounding helium. In this paper we present a systematic scan of the stability margin of all types of LHC cables working at 1.9 Kagainst transient heat depositions. We specifically discuss the dependence of the stability margin on the parameters of the model, which provide an estimate of the uncertainty of the values quoted. The stability margin calculations have been performed using a zero-dimensional (0-D) numerical model, and a cooling model taking into account the relevant helium phases which may appear during a stability experiment: it includes Kapitza thermal resistance in superfluid He, boundary layer formation and heat transfer in He I, and considers the transition from nucleating boiling to film boiling during He gas formation
Smart Avatars in JackMOO
Creation of compelling 3-dimensional, multi-user virtual worlds for education and training applications requires a high degree of realism in the appearance, interaction, and behavior of avatars within the scene. Our goal is to develop and/or adapt existing 3-dimensional technologies to provide training scenarios across the Internet in a form as close as possible to the appearance and interaction expected of live situations with human participants. We have produced a prototype system, JackMOO, which combines Jack, a virtual human system, and LambdaMOO, a multiuser, network-accessible, programmable, interactive server. Jack provides the visual realization of avatars and other objects. LambdaMOO provides the web-accessible communication, programability, and persistent object database. The combined JackMOO allows us to store the richer semantic information necessitated by the scope and range of human actions that an avatar must portray, and to express those actions in the form of imperative sentences. This paper describes JackMOO, its components, and a prototype application with five virtual human agents
Posture Interpolation with Collision Avoidance
While interpolating between successive postures of an articulated figure is not mathematically difficult, it is much more useful to provide postural transactions that are behaviorally reasonable and that avoid collisions with nearby objects. We describe such a posture interpolator which begins with a number of pre-defined static postures. A finite state machine controls the transactions from any posture to a goal posture by finding the shortest path of required motion sequences between the two. If the motion between any two postures is not collision free, a collision avoidance strategy is invoked and the posture is changed to one that satisfies the required goal while respecting object and agent integrity
Models and experimental results from the wide aperture Nb-Ti magnets for the LHC upgrade
MQXC is a Nb-Ti quadrupole designed to meet the accelerator quality
requirements needed for the phase-1 LHC upgrade, now superseded by the high
luminosity upgrade foreseen in 2021. The 2-m-long model magnet was tested at
room temperature and 1.9 K. The technology developed for this magnet is
relevant for other magnets currently under development for the high-luminosity
upgrade, namely D1 (at KEK) and the large aperture twin quadrupole Q4 (at CEA).
In this paper we present MQXC test results, some of the specialized heat
extraction features, spot heaters, temperature sensor mounting and voltage tap
development for the special open cable insulation. We look at some problem
solving with noisy signals, give an overview of electrical testing, look at how
we calculate the coil resistance during at quench and show that the heaters are
not working We describe the quench signals and its timing, the development of
the quench heaters and give an explanation of an Excel quench calculation and
its comparison including the good agreement with the MQXC test results. We
propose an improvement to the magnet circuit design to reduce voltage to ground
values by factor 2. The program is then used to predict quench Hot-Spot and
Voltages values for the D1 dipole and the Q4 quadrupole.Comment: 8 pages, Contribution to WAMSDO 2013: Workshop on Accelerator Magnet,
Superconductor, Design and Optimization; 15 - 16 Jan 2013, CERN, Geneva,
Switzerlan
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