Automatic Prediction Of Small Group Performance In Information Sharing Tasks

In this paper, we describe a novel approach, based on Markov jump processes, to model small group conversational dynamics and to predict small group performance. More precisely, we estimate conversational events such as turn taking, backchannels, turn-transitions at the micro-level (1 minute windows) and then we bridge the micro-level behavior and the macro-level performance. We tested our approach with a cooperative task, the Information Sharing task, and we verified the relevance of micro- level interaction dynamics in determining a good group performance (e.g. higher speaking turns rate and more balanced participation among group members).Comment: Presented at Collective Intelligence conference, 2012 (arXiv:1204.2991

Rank one lattice type vertex operator algebras and their automorphism groups, II: E-series

Let L be the A_1 root lattice and G a finite subgroup of Aut(V_L), where $V_L$ is the associated lattice VOA (in this case, Aut(V) is isomorphic to PSL(2,\Bbb C)). The fixed point subVOA, V^G was studied in q-alg/9710017, which finds a set of generators and determines the automorphism group when G is cyclic (from the "A-series") or dihedral (from the "D-series"). In the present article, we obtain analogous results for the remaining possibilities for G, that it belong to the "E-series": G\cong Alt_4, Alt_5 or Sym_4.Comment: Latex, 10 page

Spherically symmetric trapping horizons, the Misner-Sharp mass and black hole evaporation

Understood in terms of pure states evolving into mixed states, the possibility of information loss in black holes is closely related to the global causal structure of spacetime, as is the existence of event horizons. However, black holes need not be defined by event horizons, and in fact we argue that in order to have a fully unitary evolution for black holes, they should be defined in terms of something else, such as a trapping horizon. The Misner-Sharp mass in spherical symmetry shows very simply how trapping horizons can give rise to black hole thermodynamics, Hawking radiation and singularities. We show how the Misner-Sharp mass can also be used to give insights into the process of collapse and evaporation of locally defined black holes.Comment: 9 pages, 10 figure

PHOSGENE-FREE DIMETHYL CARBONATE PRODUCTION

A novel, phosgene-free approach to producing 100 MMlb/yr of dimethyl carbonate (DMC) was designed using a two step catalytic reaction of methanol and urea to produce DMC and ammonia. The methanol and urea were mixed and heated to drive the first step of the reaction, conversion of urea to methyl carbamate (MC). The MC and methanol mixture was fed to a high pressure reactive distillation column containing the catalyst. The reactive distillation tower strips off ammonia as it is produced, forcing the reaction forward. The ammonia vapor is then sold to an adjacent plant, which uses it to produce urea. The components of the liquid stream leaving the reactive distillation tower are separated by simple distillation towers. Excess methanol and MC are recycled back to the reactive distillation tower, leaving only the purified ammonia and DMC streams as products. Several assumptions are made in the design of this process. First, due to the lack of readily-available data or binary coefficients, the interactions of DMC and MC in a vapor-liquid equilibrium environment are estimated using ASPEN Plus. Second, the exact yield of DMC is unknown under the process conditions, though the reactive distillation tower was designed in conjunction with the chosen catalyst in such a way as to guarantee a good, predictable lower bound on the production of DMC. Finally, due to the nature in which urea is mixed with methanol at high temperature and pressure, an entirely custom solids handling system is necessary to adequately mix and react the urea and methanol. As the full details of this system are not known, the design uses an approximation of the equipment and utilities required. Based on these assumptions, the design gives a DMC production scheme that is reliable, economically feasible, and environmentally neutral