29,667 research outputs found
Leakage current and surface discharge phenomena : effect on tracking and morphological properties of LLDPE-natural rubber compounds
Polymeric insulators are widely used for high voltage outdoor insulating application due to their substantial advantages compared to the porcelain and glass insulators. Although polymer materials have been proven good, research on development of new polymerbased materials is still on going since the benefits of using polymeric materials are not yet utilised to their full potential. In this work, a new formulated thermoplastic elastomer materials that are composed of linear low-density polyethylene (LLDPE) and natural rubber (NR) filled with different loadings of alumina trihydrate (ATH) fillers is presented. A surface tracking and erosion test is conducted to investigate the characteristics of leakage current on the material surface under the influence of wet contaminated conditions. A computer-based leakage current monitoring system is developed to monitor the leakage current waveform pattern as well as its frequency spectrum. The scanning electron microscope is used to investigate the morphological properties of the materials before and after the tracking test
Revenue-productive income tax structures and tax reforms in emerging market economies - evidence from Bulgaria
Using a household budget survey for 1992, The author shows the poor revenue performance and distributional impact of Bulgaria's personal income tax system. He explores the implications for revenue and income distribution of two alternative tax systems - a flat tax and a progressive but simpler three-brackets tax system. He demonstrates that simpler tax structures with lower tax rates could achieve at least equal revenue and distributional objectives and are superior in terms of efficiency and equity. (The findings are robust when Bulgaria's significant tax evasion is included). But tax changes since 1992 have, if anything, moved Bulgaria even further from a simple income tax system: the number of rates and brackets increased from 7 to 10, and the levels of exemption remain unchanged. (Complex, higher rates complicate administration and enforcement and provide incentives for tax evasions. And in the alternative systems the author explores, the poor are protected with higher exemptions.) Fortunately, the country's personal income tax structure began to move toward less nominal progressivity after Bulgaria's 1997 tax reform program. The tax rate in thetop income bracket was reduced from 52 percent to 40 percent, the number of tax brackets was halved, and the exemption level was increased 20 percent (reducing tax burdens on the poor).Environmental Economics&Policies,Public Sector Economics&Finance,Regional Governance,Tax Policy and Administration,Economic Theory&Research,Governance Indicators,Economic Theory&Research,Public Sector Economics&Finance,Environmental Economics&Policies,Tax Policy and Administration
Nongrey radiation effects on the boundary layer of an absorbing gas over a flat plate
Nongrey radiation effects on boundary layer of absorbing gas over flat plat
Wireless Health Monitoring using Passive WiFi Sensing
This paper presents a two-dimensional phase extraction system using passive
WiFi sensing to monitor three basic elderly care activities including breathing
rate, essential tremor and falls. Specifically, a WiFi signal is acquired
through two channels where the first channel is the reference one, whereas the
other signal is acquired by a passive receiver after reflection from the human
target. Using signal processing of cross-ambiguity function, various features
in the signal are extracted. The entire implementations are performed using
software defined radios having directional antennas. We report the accuracy of
our system in different conditions and environments and show that breathing
rate can be measured with an accuracy of 87% when there are no obstacles. We
also show a 98% accuracy in detecting falls and 93% accuracy in classifying
tremor. The results indicate that passive WiFi systems show great promise in
replacing typical invasive health devices as standard tools for health care.Comment: 6 pages, 8 figures, conference pape
Distribution of income and the income tax burden in Bulgaria
Using the 1992 Bulgarian household budget survey, the authors analyze the distribution of income and of the income tax burden by income and expenditure class and by rural-urban sector. They find: 1) Low income inequality (although that is changing rapidly). 2) A progressive income tax system. The poor (the lowest two-income decile) pay only 1.4 percent of their per capita income in income tax; the rich (the top decile) pay nearly 6 percent. In-kind income and expenditures are excluded from taxation. 3) The urban sector pays proportionately more in taxes than the rural sector. For example, urban households pay 5.3 percent of their per capita income in income tax, whereas the rural sector pays 2.4 percent. 3) Income tax contributes significantly to reducing income inequality at both the national and sectoral (rural-urban) level, as the poor pay a smaller share of taxes than their share of national income. These results hold whether income or expenditure is used as an indicator of economic well-being. The authors caution that as in-kind income becomes monetized and the economy becomes more market-oriented, the system will become less progressive and urban-rural differences will diminish. They contend that the bias toward higher urban taxes is justified to some extent by the fact that urban households benefit more from government services than rural households do.Payment Systems&Infrastructure,Environmental Economics&Policies,Public Sector Economics&Finance,Economic Theory&Research,Income,Environmental Economics&Policies,Economic Theory&Research,Income,Inequality,Governance Indicators
On Euclidean Norm Approximations
Euclidean norm calculations arise frequently in scientific and engineering
applications. Several approximations for this norm with differing complexity
and accuracy have been proposed in the literature. Earlier approaches were
based on minimizing the maximum error. Recently, Seol and Cheun proposed an
approximation based on minimizing the average error. In this paper, we first
examine these approximations in detail, show that they fit into a single
mathematical formulation, and compare their average and maximum errors. We then
show that the maximum errors given by Seol and Cheun are significantly
optimistic.Comment: 9 pages, 1 figure, Pattern Recognitio
Conserved Charges and Supersymmetry in Principal Chiral Models
We report on investigations of local (and non-local) charges in bosonic and
supersymmetric principal chiral models in 1+1 dimensions. In the bosonic PCM
there is a classically conserved local charge for each symmetric invariant
tensor of the underlying group. These all commute with the non-local Yangian
charges. The algebra of the local charges amongst themselves is rather more
subtle. We give a universal formula for infinite sets of mutually commuting
local charges with spins equal to the exponents of the underlying classical
algebra modulo its Coxeter number. Many of these results extend to the
supersymmetric PCM, but with local conserved charges associated with
antisymmetric invariants in the Lie algebra. We comment briefly on the quantum
conservation of local charges in both the bosonic and super PCMs.Comment: 18 pages, LaTeX. Revised and up-dated version based on conference
talks by JME and NJ
Cosmological solutions of massive gravity on de Sitter
In the framework of the recently proposed models of massive gravity, defined
with respect to a de Sitter reference metric, we obtain new homogeneous and
isotropic solutions for arbitrary cosmological matter and arbitrary spatial
curvature. These solutions can be classified into three branches. In the first
two, the massive gravity terms behave like a cosmological constant. In the
third branch, the massive gravity effects can be described by a time evolving
effective fluid with rather remarkable features, including the property to
behave as a cosmological constant at late time.Comment: 6 pages, 1 figure; discussion extended, a few references added,
improved analysis in Section
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