328,264 research outputs found
Application of k Means Clustering algorithm for prediction of Students Academic Performance
The ability to monitor the progress of students academic performance is a
critical issue to the academic community of higher learning. A system for
analyzing students results based on cluster analysis and uses standard
statistical algorithms to arrange their scores data according to the level of
their performance is described. In this paper, we also implemented k mean
clustering algorithm for analyzing students result data. The model was combined
with the deterministic model to analyze the students results of a private
Institution in Nigeria which is a good benchmark to monitor the progression of
academic performance of students in higher Institution for the purpose of
making an effective decision by the academic planners.Comment: IEEE format, International Journal of Computer Science and
Information Security, IJCSIS January 2010, ISSN 1947 5500,
http://sites.google.com/site/ijcsis
On Dirac theory in the space with deformed Heisenberg algebra. Exact solutions
The Dirac equation has been studied in which the Dirac matrices
\hat{\boldmath\alpha}, \hat\beta have space factors, respectively and
, dependent on the particle's space coordinates. The function deforms
Heisenberg algebra for the coordinates and momenta operators, the function
being treated as a dependence of the particle mass on its position. The
properties of these functions in the transition to the Schr\"odinger equation
are discussed. The exact solution of the Dirac equation for the particle motion
in the Coulomnb field with a linear dependence of the function on the
distance to the force centre and the inverse dependence on for the
function has been found.Comment: 13 page
The H-test probability distribution revisited: Improved sensitivity
Aims: To provide a significantly improved probability distribution for the
H-test for periodicity in X-ray and -ray arrival times, which is
already extensively used by the -ray pulsar community. Also, to obtain
an analytical probability distribution for stacked test statistics in the case
of a search for pulsed emission from an ensemble of pulsars where the
significance per pulsar is relatively low, making individual detections
insignificant on their own. This information is timely given the recent rapid
discovery of new pulsars with the Fermi-LAT t -ray telescope. Methods:
Approximately realisations of the H-statistic () for random
(white) noise is calculated from a random number generator for which the
repitition cycle is . From these numbers the probability
distribution is calculated. Results: The distribution of is is
found to be exponential with parameter so that the cumulative
probability distribution . If we stack independent
values for , the sum of such values would follow the Erlang-K
distribution with parameter for which the cumulative probability
distribution is also a simple analytical expression. Conclusion: Searches for
weak pulsars with unknown pulse profile shapes in the Fermi-LAT, Agile or other
X-ray data bases should benefit from the {\it H-test} since it is known to be
powerful against a broad range of pulse profiles, which introduces only a
single statistical trial if only the {\it H-test} is used. The new probability
distribution presented here favours the detection of weaker pulsars in terms of
an improved sensitivity relative to the previously known distribution.Comment: 4 pages, two figures, to appear in Astronomy and Astrophysics,
Letter
Josephson effect in ballistic graphene
We solve the Dirac-Bogoliubov-De-Gennes equation in an impurity-free
superconductor-normal-superconductor (SNS) junction, to determine the maximal
supercurrent that can flow through an undoped strip of graphene with heavily
doped superconducting electrodes. The result is determined by the
superconducting gap and by the aspect ratio of the junction (length L, small
relative to the width W and to the superconducting coherence length). Moving
away from the Dirac point of zero doping, we recover the usual ballistic result
in which the Fermi wave length takes over from L. The product of critical
current and normal-state resistance retains its universal value (up to a
numerical prefactor) on approaching the Dirac point.Comment: 4 pages, 2 figure
Application of vertical electrical sounding method to decipher the existing subsurface stratification and groundwater occurrence status in a location in Edo North of Nigeria
The interpretation of two resistivity curves over Iyakpi town within geologic terrain often referred to as
Ajali formation which bears false-bedded sandstone with associated clay and shale intervals in the
bottom section indicates that the area has an abundant groundwater potential. Existence of productive
borehole in the study area was field-confirmed. The study area is said to have a standing history of
abortive boreholes, resulting from failed drilling attempts. No dug well was sited in the community. The
study showed that the main lithologic units penetrated by the sounding curves are laterite, sandstone,
sandstone (dry with some clay/shale). This study revealed the possibility of having a maximum drill
depth to water table of 260 m (865.80 ft)
Globalisation and Employment Generation in Nigeria’s Manufacturing Sector (1990-2006)
In this paper, we examined the effects of globalisation on employment level in the
manufacturing sector in Nigeria. The manufacturing sector is considered very important as
it is expected to be one of the key sectors absorbing the surplus agricultural labour as they
are released from the rural sector in the development process. Given the set of reforms
embarked upon since the mid-1980’s in Nigeria which are expected to lead to structural and
institutional changes such as an enhanced private sector participation in the economy and
higher employment generation, among others, we have designed this study to examine the
employment effect of globalisation in the Nigerian manufacturing. Using time series data
for the period 1990-2006, we have carried out an analysis of the impact of these reform
policies, especially those related to globalisation and employment. In addition, we have
formulated and estimated an employment model to examine the influence of several
globalisation variables used on the employment level. The result of our analysis showed
that several employment and globalisation-related variables are positively related in the
Nigerian manufacturing. Based on our findings, we have proffered some recommendations
that are capable of enhancing the employment level in the manufacturing sector of Nigeria
First-principle Wannier functions and effective lattice fermion models for narrow-band compounds
We propose a systematic procedure for constructing effective lattice fermion
models for narrow-band compounds on the basis of first-principles electronic
structure calculations. The method is illustrated for the series of
transition-metal (TM) oxides: SrVO, YTiO, VO, and
YMoO. It consists of three parts, starting from LDA. (i)
construction of the kinetic energy Hamiltonian using downfolding method. (ii)
solution of an inverse problem and construction of the Wannier functions (WFs)
for the given kinetic energy Hamiltonian. (iii) calculation of screened Coulomb
interactions in the basis of \textit{auxiliary} WFs, for which the
kinetic-energy term is set to be zero. The last step is necessary in order to
avoid the double counting of the kinetic-energy term, which is included
explicitly into the model. The screened Coulomb interactions are calculated in
a hybrid scheme. First, we evaluate the screening caused by the change of
occupation numbers and the relaxation of the LMTO basis functions, using the
conventional constraint-LDA approach, where all matrix elements of
hybridization involving the TM orbitals are set to be zero. Then, we switch
on the hybridization and evaluate the screening associated with the change of
this hybridization in RPA. The second channel of screening is very important,
and results in a relatively small value of the effective Coulomb interaction
for isolated bands. We discuss details of this screening and consider
its band-filling dependence, frequency dependence, influence of the lattice
distortion, proximity of other bands, and the dimensionality of the model
Hamiltonian.Comment: 35 pages, 25 figure
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