3,951 research outputs found
Xue Han Zi: using multimedia to teach chinese
As the Chinese-speaking areas are becoming the focus of the world economy, more and more people are attracted by their language
and culture. The number of beginners in Chinese language is growing rapidly. Although the Chinese language has unique characteristics, there are still very few teaching and learning materials which serve the basic needs for starting the acquisition of Han Zi.
A multimedia application, both in CD-ROM and on-line, can provide a virtual teacher for understanding and learning Chinese writing at an elementary level and, without doubt, can attract more learners
Interpolating gauge fixing for Chern-Simons theory
Chern-Simons theory is analyzed with a gauge-fixing which allows to discuss
the Landau gauge and the light-cone gauge at the same time.Comment: 11 pages, Report TUW-93-2
Static output-feedback stabilization of discrete-time Markovian jump linear systems: a system augmentation approach
This paper studies the static output-feedback (SOF) stabilization problem for discrete-time Markovian jump systems from a novel perspective. The closed-loop system is represented in a system augmentation form, in which input and gain-output matrices are separated. By virtue of the system augmentation, a novel necessary and sufficient condition for the existence of desired controllers is established in terms of a set of nonlinear matrix inequalities, which possess a monotonic structure for a linearized computation, and a convergent iteration algorithm is given to solve such inequalities. In addition, a special property of the feasible solutions enables one to further improve the solvability via a simple D-K type optimization on the initial values. An extension to mode-independent SOF stabilization is provided as well. Compared with some existing approaches to SOF synthesis, the proposed one has several advantages that make it specific for Markovian jump systems. The effectiveness and merit of the theoretical results are shown through some numerical example
Clustering Evolutionary Stock Market Model
As a typical representation of complex networks studied relatively
thoroughly, financial market presents some special details, such as its
nonconservation and opinions spreading. In this model, agents congregate to
form some clusters, which may grow or collapse with the evolution of the
system. To mimic an open market, we allow some ones participate in or exit the
market suggesting that the number of the agents would fluctuate. Simulation
results show that the large events are frequent in the fluctuations of the
stock price generated by the artificial stock market when compared with a
normal process and the price return distribution is a \emph{l\'{e}vy}
distribution in the central part followed by an approximately exponential
truncation.Comment: 9 pages, 8 figure
Intraspecfic variation in cold-temperature metabolic phenotypes of Arabidopsis lyrata ssp petraea
Atmospheric temperature is a key factor in determining the distribution of a plant species. Alongside this, plant populations growing at the margin of their range may exhibit traits that indicate genetic differentiation and adaptation to their local abiotic environment. We investigated whether geographically separated marginal populations of Arabidopsis lyrata ssp. petraea have distinct metabolic phenotypes associated with exposure to cold temperatures. Seeds of A. petraea were obtained from populations along a latitudinal gradient, namely Wales, Sweden and Iceland and grown in a controlled cabinet environment. Mannose, glucose, fructose, sucrose and raffinose concentrations were different between cold treatments and populations, especially in the Welsh population, but polyhydric alcohol concentrations were not. The free amino acid compositions were population specific, with fold differences in most amino acids, especially in the Icelandic populations, with gross changes in amino acids, particularly those associated with glutamine metabolism. Metabolic fingerprints and profiles were obtained. Principal component analysis (PCA) of metabolite fingerprints revealed metabolic characteristic phenotypes for each population and temperature. It is suggested that amino acids and carbohydrates were responsible for discriminating populations within the PCA. Metabolite fingerprinting and profiling has proved to be sufficiently sensitive to identify metabolic differences between plant populations at different atmospheric temperatures. These findings show that there is significant natural variation in cold metabolism among populations of A. l. petraea which may signify plant adaptation to local climates
HERANÇA DA RESISTÊNCIA AO CANCRO DA HASTE (Diaporthe phaseolorum (Cke.& Ell). Sacc.F.sp. Meridionalis Morgan Jones) EM SOJA (Glycine max (L.) Merrill)
Genótipos de soja com diferentes reações frente a um isolado de Diaporthe phaseolorum f. sp. Meridionalis foram cruzados para o estudo da herança da resistência. As reações dos parentais e da população progênie foram estudadas em condições artificiais de inoculação, utilizando o “método do palito”. O cruzamento entre a linhagem ‘J-118’ (resistente) e o cultivar ‘BR-23’ (suscetível) apresentou na geração F1’, todas as plantas resistentes e, na geração F2, uma proporção de três plantas para uma suscetível, mostrando que há resistência para uma suscetível, mostrando que a resistência na linhagem “J-118” é condicionada por um gene dominante. O cruzamento entre dois cultivares suscetíveis, J-200 e BR-23, não apresentou, na população segregante, qualquer nível de resistência
Strength, stiffness and ductility of concrete-filled steel columns under axial compression
YesExtensive experimental and theoretical studies have been conducted on the compressive strength of concrete-filled steel tubular (CFST) columns, but little attention has been paid to their compressive stiffness and deformation capacity. Despite this, strength prediction approaches in existing design codes still have various limitations. A finite element model, which was previously proposed by the authors and verified using a large amount of experimental data, is used in this paper to generate simulation data covering a wide range of parameters for circular and rectangular CFST stub columns under axial compression. Regression analysis is conducted to propose simplified models to predict the compressive strength, the compressive stiffness, and the compressive strain corresponding to the compressive strength (ductility) for the composite columns. Based on the new strength prediction model, the capacity reduction factors for the steel and concrete materials are recalibrated to achieve a target reliability index of 3.04 when considering resistance effect only
NETRA: Interactive Display for Estimating Refractive Errors and Focal Range
We introduce an interactive, portable, and inexpensive solution for estimating refractive errors in the human eye. While expensive optical devices for automatic estimation of refractive correction exist, our goal is to greatly simplify the mechanism by putting the human subject in the loop. Our solution is based on a high-resolution programmable display and combines inexpensive optical elements, interactive GUI, and computational reconstruction. The key idea is to interface a lenticular view-dependent display with the human eye in close range - a few millimeters apart. Via this platform, we create a new range of interactivity that is extremely sensitive to parameters of the human eye, like refractive errors, focal range, focusing speed, lens opacity, etc. We propose several simple optical setups, verify their accuracy, precision, and validate them in a user study.Alfred P. Sloan Foundation (Research Fellowship
Working memory capacity limits motor learning when implementing multiple instructions.
Although it is generally accepted that certain practice conditions can place large
demands on working memory (WM) when performing and learning a motor skill, the
influence that WM capacity has on the acquisition of motor skills remains
unsubstantiated. This study examined the role of WM capacity in a motor skill practice
context that promoted WM involvement through the provision of explicit instructions. A
cohort of 90 children aged 8 to 10 years were assessed on measures of WM capacity
and attention. Children who scored in the lowest and highest thirds on the WM tasks
were allocated to lower WM capacity (n D 24) and higher WM capacity (n D 24) groups,
respectively. The remaining 42 participants did not participate in the motor task. The
motor task required children to practice basketball shooting for 240 trials in blocks of 20
shots, with pre- and post-tests occurring before and after the intervention. A retention
test was administered 1 week after the post-test. Prior to every practice block, children
were provided with five explicit instructions that were specific to the technique of
shooting a basketball. Results revealed that the higher WM capacity group displayed
consistent improvements from pre- to post-test and through to the retention test, while
the opposite effect occurred in the lower WM capacity group. This implies that the
explicit instructions had a negative influence on learning by the lower WM capacity
children. Results are discussed in relation to strategy selection for dealing with
instructions and the role of attention control
EPW: A program for calculating the electron-phonon coupling using maximally localized Wannier functions
EPW (Electron-Phonon coupling using Wannier functions) is a program written
in FORTRAN90 for calculating the electron-phonon coupling in periodic systems
using density-functional perturbation theory and maximally-localized Wannier
functions. EPW can calculate electron-phonon interaction self-energies,
electron-phonon spectral functions, and total as well as mode-resolved
electron-phonon coupling strengths. The calculation of the electron-phonon
coupling requires a very accurate sampling of electron-phonon scattering
processes throughout the Brillouin zone, hence reliable calculations can be
prohibitively time-consuming. EPW combines the Kohn-Sham electronic eigenstates
and the vibrational eigenmodes provided by the Quantum-ESPRESSO package [1]
with the maximally localized Wannier functions provided by the wannier90
package [2] in order to generate electron-phonon matrix elements on arbitrarily
dense Brillouin zone grids using a generalized Fourier interpolation. This
feature of EPW leads to fast and accurate calculations of the electron-phonon
coupling, and enables the study of the electron-phonon coupling in large and
complex systems.Comment: 6 figure
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