3,000 research outputs found

    On the Geometry of the Moduli Space of Real Binary Octics

    Full text link
    The moduli space of smooth real binary octics has five connected components. They parametrize the real binary octics whose defining equations have 0, 1, ..., 4 complex-conjugate pairs of roots respectively. We show that the GIT-stable completion of each of these five components admits the structure of an arithmetic real hyperbolic orbifold. The corresponding monodromy groups are, up to commensurability, discrete hyperbolic reflection groups, and their Vinberg diagrams are computed. We conclude with a simple proof that the moduli space of GIT-stable real binary octics itself cannot be a real hyperbolic orbifold.Comment: 23 page

    Profiling time course expression of virus genes---an illustration of Bayesian inference under shape restrictions

    Get PDF
    There have been several studies of the genome-wide temporal transcriptional program of viruses, based on microarray experiments, which are generally useful in the construction of gene regulation network. It seems that biological interpretations in these studies are directly based on the normalized data and some crude statistics, which provide rough estimates of limited features of the profile and may incur biases. This paper introduces a hierarchical Bayesian shape restricted regression method for making inference on the time course expression of virus genes. Estimates of many salient features of the expression profile like onset time, inflection point, maximum value, time to maximum value, area under curve, etc. can be obtained immediately by this method. Applying this method to a baculovirus microarray time course expression data set, we indicate that many biological questions can be formulated quantitatively and we are able to offer insights into the baculovirus biology.Comment: Published in at http://dx.doi.org/10.1214/09-AOAS258 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

    THE EFFECT OF MYOELECTRIC STIMULATION ON PERONEAL MUSCLES TO RESIST SUDDEN SIMULATED ANKLE SPRAIN MOTIONS

    Get PDF
    This study evaluated the effect of myoelectric stimulation on peroneal muscles to resist sudden simulated ankle sprain motions. Ten male subjects performed unanticipated inversion and supination spraining motions simulated by a mechanical sprain simulator. Myoelectric stimulations with different delay time were delivered to the peroneal muscles to initiate involuntary muscle contraction and ankle joint pronation torque to resist the spraining motion. The motion was captured and analyzed by a motion analysis system, and was quantified by the reduction of maximum heel tilting angle and angular velocity. Results showed significant effect in all conditions with the myoelectric stimulation of any delay time within 15ms. The maximum heel tilting angle and angular velocity dropped from 18 to 9-13 degrees and from 200-250 to 140-170 degree/s respectively. The present corrective mechanism could be implemented in our current research to develop an intelligent sprain-free sport shoe attempting to prevent ankle sprain injury in sports

    ACER eNews 01 January 2007

    Get PDF
    This paper presents a centralized control system that coordinates parallel operations of different distributed generation (DG) inverters within a microgrid. The control design for the DG inverters employs a new Model Predictive Control algorithm that allows faster computational time for large power systems by optimizing the steady-state and the transient control problems separately. An overall energy management system is also implemented for the microgrid to coordinate load sharing among different DG units during both grid-connected and islanded operations. The design concept of the proposed control system is evaluated through simulation studies under different test scenarios. The impact of the increased penetration of DG units on the distribution grid is also investigated using the proposed microgrid. The simulation results show that the operations of the DG units within the microgrid can be coordinated effectively under the proposed control system to ensure stable operation of the overall microgrid

    Assessment of Ocean Wave Model used to Analyze the Constellation Program (CxP) Orion Project Crew Module Water Landing Conditions

    Get PDF
    Mr. Christopher Johnson, NASA's Systems Manager for the Orion Project Crew Module (CM) Landing and Recovery at the Johnson Space Center (JSC), and Mr. James Corliss, Project Engineer for the Orion CM Landing System Advanced Development Project at the Langley Research Center (LaRC) requested an independent assessment of the wave model that was developed to analyze the CM water landing conditions. A NASA Engineering and Safety Center (NESC) initial evaluation was approved November 20, 2008. Mr. Bryan Smith, NESC Chief Engineer at the NASA Glenn Research Center (GRC), was selected to lead this assessment. The Assessment Plan was presented and approved by the NESC Review Board (NRB) on December 18, 2008. The Assessment Report was presented to the NRB on March 12, 2009. This document is the final Assessment Report

    Direct Instantons in QCD Nucleon Sum Rules

    Full text link
    We study the role of direct (i.e. small-scale) instantons in QCD correlation functions for the nucleon. They generate sizeable, nonperturbative corrections to the conventional operator product expansion, which improve the quality of both QCD nucleon sum rules and cure the long-standing stability problem, in particular, of the chirally odd sum-rule.Comment: 10 pages, UMD PP#93-17

    Graphene-based modulation-doped superlattice structures

    Full text link
    The electronic transport properties of graphene-based superlattice structures are investigated. A graphene-based modulation-doped superlattice structure geometry is proposed and consist of periodically arranged alternate layers: InAs/graphene/GaAs/graphene/GaSb. Undoped graphene/GaAs/graphene structure displays relatively high conductance and enhanced mobilities at elevated temperatures unlike modulation-doped superlattice structure more steady and less sensitive to temperature and robust electrical tunable control on the screening length scale. Thermionic current density exhibits enhanced behaviour due to presence of metallic (graphene) mono-layers in superlattice structure. The proposed superlattice structure might become of great use for new types of wide-band energy gap quantum devices.Comment: 5 figure
    corecore