657 research outputs found
e-Collaboration for Tertiary Education Using Mobile Systems
Electronic collaboration has revolutionized academic activities by enabling academic collaborations through devices such ascomputers and other mobile devices. With this development, learning and academic collaboration can now take place acrosscontinents and different time zones. In electronic collaboration, knowledge sharing is done remotely, in real-time and notlocation-bound. Although several institutions in the developed countries have been using some form of eCollaboration foracademic activities and for improving collaborations among students, much has not been done in this domain in thedeveloping world. Using Java as software technology of choice, we take electronic learning a step further by making itpossible for students to learn and collaborate through mobile phones thus leveraging on the existing mobile diffusion amongstudents in Nigeria. The intention is to contribute to research and development in mobile learning relevant to the growth andquality of education by encouraging group participation among students and fostering joint academic contributions amongthe academia.KEYWORDS: Electronic collaboration, Mobile collaboration software, mobile phone and electronic learning
Analysis of radio frequency spectrum usage using cognitive radio
This paper presents the analysis of radio frequency (RF) spectrum usage using cognitive radio. The aim was to determine the unused spectrum frequency bands for efficiently utilization. A program was written to reuse a range of vacant frequency with different model element working together to produce a spectrum sensing in MATLAB/Simulink environment. The developed Simulink model was interfaced with a register transfer level - software defined radio, which measures the estimated noise power of the received signal over a given time and bandwidth. The threshold estimation performed generates a 1\0 output for decision and prediction. It was observed that some spectrum, identified as vacant frequency, were underutilized in FM station in Benin City. The result showed that when cognitive radio displays “1” output, which is decision H1, the channel is occupied and cannot be used by the cognitive radio for communication. Conversely, when “0” output (decision H0) is displayed, the channel is unoccupied. There is a gradual decrease in the probability of detection (Pd), when the probability of false alarm (Pfa) is increased from 1% to 5%. In the presence of higher Pfa, the Pd of the receiver maintains a high stability. Hence, the analysis finds the spectrum hole and identifies how it can be reuse
Women's role in reproductive health decision making and vulnerability to STD and HIV/AIDS in Ekiti, Nigeria
An exploratory study of women’s role in reproductive decision making in Ekiti shows that women in the state are increasingly taking active decisions on matters affecting their daily lives. More women than ever before believed that they could take decisions on family size, when to have a baby and choice of spacing period. The cultural barrier against short postpartum abstinence appeared to have diminished and sex during lactation was not considered a major cultural and religious taboo. Knowledge of contraception has become universal in recent years, and the majority of women take decisions on the method and timing of family planning. All women who used family planning considered their decision in this regard very important. The ability of women to take decisions on these issues may not only enhance their bargaining power but also reduce their vulnerability to STDs including AIDS from diseased or high-risk partners
Data-Oriented Declarative Language for Optimizing Business Processes
There is a signifi cant number of declarative languages to describe business
processes. They tend to be used when business processes need to be fl exible and
adaptable, being not possible to use an imperative description. Declarative languages
in business process have been traditionally used to describe the order of
activities, specifi cally the order allowed or prohibited. Unfortunately, none of them
is worried about a declarative description of exchanged data between the activities
and how they can infl uence the model. In this paper, we analyse the data description
capacity of a variety of declarative languages in business processes. Using this
analysis, we have detected the necessity to include data exchanged aspects in the
declarative descriptions. In order to solve the gap, we propose a Data-Oriented
Optimization Declarative LanguagE, called DOODLE, which includes the process
requirements referred to data description, and the possibility to include an optimization
function about the process output data
Coherent states for polynomial su(1,1) algebra and a conditionally solvable system
In a previous paper [{\it J. Phys. A: Math. Theor.} {\bf 40} (2007) 11105],
we constructed a class of coherent states for a polynomially deformed
algebra. In this paper, we first prepare the discrete representations of the
nonlinearly deformed algebra. Then we extend the previous procedure
to construct a discrete class of coherent states for a polynomial su(1,1)
algebra which contains the Barut-Girardello set and the Perelomov set of the
SU(1,1) coherent states as special cases. We also construct coherent states for
the cubic algebra related to the conditionally solvable radial oscillator
problem.Comment: 2 figure
A Compact Solid State Detector for Small Angle Particle Tracking
MIDAS (MIcrostrip Detector Array System) is a compact silicon tracking
telescope for charged particles emitted at small angles in intermediate energy
photonuclear reactions. It was realized to increase the angular acceptance of
the DAPHNE detector and used in an experimental program to check the
Gerasimov-Drell-Hearn sum rule at the Mainz electron microtron, MAMI. MIDAS
provides a trigger for charged hadrons, p/pi identification and particle
tracking in the region 7 deg < theta < 16 deg. In this paper we present the
main characteristics of MIDAS and its measured performances.Comment: 13 pages (9 figures). Submitted to NIM
Equilibrium Properties of A Monomer-Monomer Catalytic Reaction on A One-Dimensional Chain
We study the equilibrium properties of a lattice-gas model of an catalytic reaction on a one-dimensional chain in contact with a reservoir
for the particles. The particles of species and are in thermal contact
with their vapor phases acting as reservoirs, i.e., they may adsorb onto empty
lattice sites and may desorb from the lattice. If adsorbed and
particles appear at neighboring lattice sites they instantaneously react and
both desorb. For this model of a catalytic reaction in the
adsorption-controlled limit, we derive analytically the expression of the
pressure and present exact results for the mean densities of particles and for
the compressibilities of the adsorbate as function of the chemical potentials
of the two species.Comment: 19 pages, 5 figures, submitted to Phys. Rev.
Monitoring international migration flows in Europe. Towards a statistical data base combining data from different sources
The paper reviews techniques developed in demography, geography and statistics that are useful for bridging the gap between available data on international migration flows and the information required for policy making and research. The basic idea of the paper is as follows: to establish a coherent and consistent data base that contains sufficiently detailed, up-to-date and accurate information, data from several sources should be combined. That raises issues of definition and measurement, and of how to combine data from different origins properly. The issues may be tackled more easily if the statistics that are being compiled are viewed as different outcomes or manifestations of underlying stochastic processes governing migration. The link between the processes and their outcomes is described by models, the parameters of which must be estimated from the available data. That may be done within the context of socio-demographic accounting. The paper discusses the experience of the U.S. Bureau of the Census in combining migration data from several sources. It also summarizes the many efforts in Europe to establish a coherent and consistent data base on international migration.
The paper was written at IIASA. It is part of the Migration Estimation Study, which is a collaborative IIASA-University of Groningen project, funded by the Netherlands Organization for Scientific Research (NWO). The project aims at developing techniques to obtain improved estimates of international migration flows by country of origin and country of destination
First measurement of the Gerasimov-Drell-Hearn integral for Hydrogen from 200 to 800 MeV
A direct measurement of the helicity dependence of the total photoabsorption
cross section on the proton was carried out at MAMI (Mainz) in the energy range
200 < E_gamma < 800 MeV. The experiment used a 4 detection system, a
circularly polarized tagged photon beam and a frozen spin target.
The contributions to the Gerasimov-Drell-Hearn sum rule and to the forward
spin polarizability determined from the data are 226 \pm 5 (stat)\pm
12(sys) \mu b and -187 \pm 8 (stat)\pm 10(sys)10^{-6} fm^4, respectively, for
200 < E_\gamma < 800 MeV.Comment: 6 pages, 3 figures, 3 table
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