Interaction Capture and Synthesis

Special Issue: ACM SIGGRAPH 2006International audienceModifying motion capture to satisfy the constraints of new animation is difficult when contact is involved, and a critical problem for animation of hands. The compliance with which a character makes contact also reveals important aspects of the movement's purpose. We present a new technique called interaction capture, for capturing these contact phenomena. We capture contact forces at the same time as motion, at a high rate, and use both to estimate a nominal reference trajectory and joint compliance. Unlike traditional methods, our method estimates joint compliance without the need for motorized perturbation devices. New interactions can then be synthesized by physically based simulation. We describe a novel position-based linear complementarity problem formulation that includes friction, breaking contact, and the compliant coupling between contacts at different fingers. The technique is validated using data from previous work and our own perturbation-based estimates

HCI for the deaf community: developing human-like avatars for sign language synthesis

With ever increasing computing power and advances in 3D animation technologies it is no surprise that 3D avatars for sign language (SL) generation are advancing too. Traditionally these avatars have been driven by somewhat expensive and inflexible motion capture technologies and perhaps this is the reason avatars do not feature in all but a few user interfaces (UIs). SL synthesis is a competing technology that is less costly, more versatile and may prove to be the answer to the current lack of access for the Deaf in HCI. This paper outlines the current state of the art in SL synthesis for HCI and how we propose to advance this by improving avatar quality and realism with a view to ameliorating communication and computer interaction for the Deaf community as part of a wider localisation project

The economics of currency crises and contagion: an introduction

Two theories of the causes of currency crises prevail in the economic literature. The first traces currency instability to countries' structural imbalances and weak policies; the second identifies arbitrary shifts in market expectations as the principal source of instability. The authors of this article contend that only a synthesis of these theories can capture the complexity of the 1997-98 Asian currency crisis. In their view, the crisis resulted from the interaction of structural weaknesses and volatile international capital markets. The authors also cite two other factors that contributed to the severity of the Asia crisis: inadequate supervision of the banking and financial sectors and the rapid transmission of the crisis across countries linked by trade and common credit sources.Financial crises ; Financial crises - Asia ; Asia

Protein Microarray On-Demand: A Novel Protein Microarray System

We describe a novel, simple and low-cost protein microarray strategy wherein the microarrays are generated by printing expression ready plasmid DNAs onto slides that can be converted into protein arrays on-demand. The printed expression plasmids serve dual purposes as they not only direct the synthesis of the protein of interest; they also serve to capture the newly synthesized proteins through a high affinity DNA-protein interaction. To accomplish this we have exploited the high-affinity binding (∼3–7×10 −13 M) of E. coli Tus protein to Ter, a 20 bp DNA sequence involved in the regulation of E. coli DNA replication. In our system, each protein of interest is synthesized as a Tus fusion protein and each expression construct directing the protein synthesis contains embedded Ter DNA sequence. The embedded Ter sequence functions as a capture reagent for the newly synthesized Tus fusion protein. This “all DNA” microarray can be converted to a protein microarray on-demand without need for any additional capture reagent.

Predictive Control for Alleviation of Gust Loads on Very Flexible Aircraft

In this work the dynamics of very flexible aircraft are described by a set of non-linear, multi-disciplinary equations of motion. Primary structural components are represented by a geometrically-exact composite beam model which captures the large dynamic deformations of the aircraft and the interaction between rigid-body and elastic degrees-of-freedom. In addition, an implementation of the unsteady vortex-lattice method capable of handling arbitrary kinematics is used to capture the unsteady, three-dimensional flow-eld around the aircraft as it deforms. Linearization of this coupled nonlinear description, which can in general be about a nonlinear reference state, is performed to yield relatively high-order linear time-invariant state-space models. Subsequent reduction of these models using standard balanced truncation results in low-order models suitable for the synthesis of online, optimization-based control schemes that incorporate actuator constraints. Predictive controllers are synthesized using these reduced-order models and applied to nonlinear simulations of the plant dynamics where they are shown to be superior to equivalent optimal linear controllers (LQR) for problems in which constraints are active

The Effects of Binary Evolution on the Dynamics of Core Collapse and Neutron-Star Kicks

We systematically examine how the presence in a binary affects the final core structure of a massive star and its consequences for the subsequent supernova explosion. Interactions with a companion star may change the final rate of rotation, the size of the helium core, the strength of carbon burning and the final iron core mass. Stars with initial masses larger than \sim 11\Ms that experiece core collapse will generally have smaller iron cores at the time of the explosion if they lost their envelopes due to a previous binary interaction. Stars below \sim 11\Ms, on the other hand, can end up with larger helium and metal cores if they have a close companion, since the second dredge-up phase which reduces the helium core mass dramatically in single stars does not occur once the hydrogen envelope is lost. We find that the initially more massive stars in binary systems with masses in the range 8 - 11\Ms are likely to undergo an electron-capture supernova, while single stars in the same mass range would end as ONeMg white dwarfs. We suggest that the core collapse in an electron-capture supernova (and possibly in the case of relatively small iron cores) leads to a prompt explosion rather than a delayed neutrino-driven explosion and that this naturally produces neutron stars with low-velocity kicks. This leads to a dichotomous distribution of neutron star kicks, as inferred previously, where neutron stars in relatively close binaries attain low kick velocities. We illustrate the consequences of such a dichotomous kick scenario using binary population synthesis simulations and discuss its implications. This scenario has also important consequences for the minimum initial mass of a massive star that becomes a neutron star. (Abbreviated.)Comment: 8 pages, 3 figures, submitted to ApJ, updated versio

Main restrictions in the synthesis of new superheavy elements: quasifission or/and fusion-fission

The synthesis of superheavy elements stimulates the effort to study the peculiarities of the complete fusion with massive nuclei and to improve theoretical models in order to extract knowledge about reaction mechanism in heavy ion collisions at low energies. We compare the theoretical results of the compound nucleus (CN) formation and evaporation residue (ER) cross sections obtained for the $^{48}$Ca+$^{248}$Cm and $^{58}$Fe+$^{232}$Th reactions leading to the formation of the isotopes A=296 and A=290, respectively, of the new superheavy element Lv (Z=116). The ER cross sections, which can be measured directly, are determined by the complete fusion and survival probabilities of the heated and rotating compound nucleus. That probabilities can not be measured unambiguously but the knowledge about them is important to study the formation mechanism of the observed products. For this aim, the $^{48}$Ca+$^{249}$Cf and $^{64}$Ni+$^{232}$Th reactions have been considered too. The use of the mass values of superheavy nuclei calculated in the framework of the macroscopic-microscopic model by Warsaw group leads to smaller ER cross section for all of the reactions (excluding the $^{64}$Ni+$^{232}$Th reaction) in comparison with the case of using the masses calculated by Peter M\"oller {\it et al}.Comment: 26 pages and 15 figures. arXiv admin note: text overlap with arXiv:1109.201

Exploring the Effects of Different Classroom Environments on the Learning Process. Synthesis of Thiazole-Linked Porous Organic Polymers for CO2 Separation and Nitro-Aromatics Sensing.

When attempting to study the learning process of undergraduate chemistry student, the classroom and any interaction that take place within it constitute the social context of interest. By studying how different approaches can foster different classroom environments, it is possible to approach course design from an informed and scientifically sound perspective. Thus, it becomes necessary to identify and quantify the factors that have a positive or negative effect on the classroom environment. Social comparison concerns, comfort levels and self-efficacy have been shown to be social factors that affect each other as well as the learning process and have therefore been deemed suitable for use in this study. POGIL, a pedagogic approach to teaching chemistry based on small-group work and active learning, has been shown to lead to positive academic outcomes and is currently employed by several faculties at Virginia Commonwealth University. This study seeks to investigate differences in the learning environment observed in lecture and POGIL based chemistry courses, by adapting Micari’s survey for measuring social comparison, comfort levels and self-efficacy in small-group science learning. Reliance on the combustion of fossil-fuels, such as coal, oil and natural gas, as sources of energy has, since the industrial revolution, caused atmospheric CO2 to increase to the current level of 400ppm by volume; an increase of 25% from the 1960s when monitoring started. Climatologists predict that an increase to 450 ppm would have irreversible effects on the Earth’s environment and recommend that, in order to preserve the conditions in which civilization developed, levels be reduced to below 350 ppm. The use of porous organic polymers for capture and separation of CO2 from industrial sources has been at the forefront of research attempting to curb CO2 emission into the atmosphere. Benzimidazole based polymers have shown a high selectivity for CO2.7 To attempt to improve on the capture abilities of these polymers, we sought to synthesize sulfur containing analogs presenting thiazole moieties. Two such polymers were synthesized using a pyrene-based linker. Furthermore, the pyrene-derived fluorescence of these polymers enabled their use as chemosensors targeting nitroaromatic compounds and mercur