An adaptive finite volume method using thin plate splines for the numerical simulation of the inviscid Burgers’ equation
August 2010
Thin plate splines are utilized in the construction of a non-oscillatory finite volume method for the inviscid Burgers’ equation which is a prototype nonlinear conservation law. To capture the sharp features that occur during numerical simulation, the method is implemented on an adaptive triangulation. An a posteriori error indicator is used to detect regions where the solution...
Population prediction using artificial neural network
August 2010
Recently, the use of mobile applications in knowledge management systems has been a majordiscussion in some literatures. In the past, the author’s conceptualized and designs a knowledge management system for “Ifa”. In this paper, a mobile application is designed which applies mobile knowledge management (mKM) to the “ifa” oracle consultation process...
An improved chaotic encryption scheme
August 2010
In this paper, an attempt is made to develop a functional encryption scheme by exploiting the strength and redefining the operational limits of two related existing schemes. Various parameters used for comparative assessment show that the proposed scheme is better than the existing ones in terms of functionality, strength and suitability for applications in securing messages on networks and work...
An empirical mathematical model for smoke attributed mortality
August 2010
This paper presents a simple empirical mathematical model which predicts the increase in mortality caused by cigarette smoking. The model considers the introduction of new brands of cigarette in the market and (or) the introduction of new smokers in a given population. The model is used to predict the smoke attributed mortality (SAM) for a period of 20 years, say, using empirical data of Nigeria population....
Appraising of Monte Carlo forecast in nonlinear econometric models
August 2010
In the study, Monte Carlo (stochastic) and deterministic forecasts have been carried out. Though, as would be expected, there is reasonable gain in efficiency in the Monte Carlo forecast over the deterministic procedure. The extent of this gain depends on the relative dispersion criterion used. Key words: Monte Carlo forecast, deterministic forecast, efficiency
A stochastic iteration method for a class of variational inequalities in Hilbert space
August 2010
Enhancing students interest in mathematics via multimedia presentation
July 2010
Alarming statistics in mathematics education in Nigeria indicated that very few or almost none of the students in high school fancy taking up a course in mathematics in the University. Moreover, less than ten percent of these students enjoyed lessons in mathematics. Additionally, cultural and racial prejudice as well as poverty are serious issues confronting many of today's high school students, thus a set of thirty...
A mobile-based knowledge management system for “Ifaâ€: An African traditional oracle
July 2010
Recently, the use of mobile applications in knowledge management systems has been a major discussion in some literatures. In the past, the author’s conceptualized and designs a knowledge management system for “Ifa”. In this paper, a mobile application is designed which applies mobile knowledge management (mKM) to the “ifa” oracle consultation process...
Visualization RCD (reinforced concrete design) table advisor for decision support activity
July 2010
Reinforced concrete design (RCD) activity requires the services of design table to pick bar sizes and area of specific bar groups. This allow reinforced concrete (RC) designers to use their intuition to pick the right bar size for detailing of RC Structures which virtually enhance reliable and satisfactory answers to RCD problems. With the advent of computer with its powerful memory, most RCD software available...
Norm properties of operators whose norms are Eigenvalues
July 2010
In this paper we present properties of a norm-attaining operator on a Hilbert space and there implications. We show that if T has norm attaining vector then where the scalars are nonnegative numbers. Thus T satisfies a generalized Daugavet condition. Key words: Numerical range, eigenvalue, normalloid...
Computing leaf rectangularity index: An estimation problem when the parameter is a norm of a vector
June 2010
A measure known as leaf rectangularity index (LRI) is estimated by means of bootstrap regression. The index, it is envisaged, will assist in discussing the geometry of leaf surfaces, if possible among different plants and across species. The study shows that one cannot obtain the point estimate of LRI before its interval estimate; rather, the interval estimate comes first before the point estimate. This paper gives the...
Subclasses of analytic functions associated with Wright generalized hypergeometric functions
June 2010
In this paper, we define a generalized class of starlike functions with negative coefficients and obtain coefficient estimates, distortion bounds, closure theorems and extreme points. Further we obtain modified Hadamard product, radii of close-to-convex, starlikeness and convexity for functions belonging to this class. Furthermore neighborhood results are discussed. Key words: Univalent functions, convex...
A novel analytical solution of steady flow over a rotating disk in porous medium with heat transfer by DTM-PADÉ
June 2010
In this study, the differential transform method (DTM) was applied to steady flow over a rotating disk in porous medium with heat transfer. The governing equations can be written as a system of nonlinear ordinary differential equations. The approximate solutions of these equations were obtained in the form of series with easily computable terms. Then, Padé approximant was applied to increase the convergence...
A mathematical model of radioimmunotherapy for tumor treatment
June 2010
There is rapidly growing interest in the potential for synergistic, clinically relevant therapeutic responses by combining radiation therapy with immune response. A new mathematical model of radioimmunotherapy for tumor treatment was introduced. In this work, the linear and exponential spatial dependence of tumor parameters was used. The dose distributions model of radiotherapy with immune response for tumor treatment...
Heat transfer over an unsteady porous stretching surface embedded in a porous medium with variable heat flux in the presence of heat source or sink
May 2010
The unsteady boundary layer flow over a porous stretching surface embedded in a porous medium in the presence of heat source or sink is studied. The unsteadiness in the flow and temperature fields is caused by the time dependence of the stretching velocity and the surface heat flux. The governing partial differential equations are transformed into a system of ordinary differential equations, which is then solved...
New generalizations of generalized geometric series distributions
May 2010
New generalizations of generalized geometric series distributions (NGOGGSD) and some of its subclasses are introduced. Recurrence relations and factorial moments are obtained. Several properties of NGOGGSD and its relations with other distributions are also discussed. Finally, a computer programmed in R-Software has been developed to ease the computations while estimating the parameters for data. Some sports sets of...
Some structural compatibilities of pre A*-algebra
April 2010
A pre A*-algebra is the algebraic form of the 3-valued logic. In this paper, we define a binary operation on pre A*-algebra and show that is a semilattice. We also prove some results on the partial ordering which is induced from the semilattice. We derive necessary and sufficient conditions for pre A*-algebra (A,Ù,Ú, (-)~) to become a Boolean algebra in terms of this partial...
Estimation of T- period’s ahead extreme quantile autoregression function
April 2010
This paper considers the estimation of extreme quantile autoregression function by using a parametric model. We combine direct estimation of quantiles in the middle region with that of extreme parts using the model and results from extreme value theory (EVT). The volatility used to scale the residuals is estimated indirectly, without estimating conditional mean, using the conditional quantile (CQ) range. The estimators...
Measuring the stress, strain and strain-rate in heat treated medium carbon steel samples and finding the constituted material related properties
March 2010
Mechanical failure of component parts as well as in build up structures can be prevented if proper quality control is carried out at point of component’s manufacture. Engineers are known to analyze samples from which accurate predictions are made about the properties of the materials that are produced for the purpose of component and structural processing. This work had produced and tested heat treated 1030 steel...
Principal component procedure in factor analysis and robustness
March 2010
Principal component procedure has been widely used in factor analysis as a data reduction procedure. The estimation of the covariance and correlation matrix in factor analysis using principal component procedure is strongly influenced by outliers. This study investigates the robustness of principal component procedure in factor analysis by generating random variables from five different distributions which are used to...
Conflict resolution using statistical approach
February 2010
Conflict can be described as a condition in which actions of one person prevent or compel some outcome at the resistance of the other. Quite often this can be seen as “two or more competing, often incompatible, responses to same event”. In this paper, a statistical approach to conflict resolution using the concept of bargaining game theory is presented. The approach gives chances of failure that are minimal...
Relationship between continuity and momentum equation in two dimensional flow
February 2010
In this paper a quantitative discussion on a theory describing the relationship between the continuity and momentum equation in two dimensional flow together with the momentum equation in vectorial form: is reported. Via expanding in cylindrical polar coordinates, the end result is proved to be Euler equation. Key word: Continuity equation, momentum equation, cylindrical coordinates,...
Invariance of numerical range under isometric transformation
February 2010
In this paper, we look at some properties of isometries and conditions for a quasi-affinity to be unitary. Among other results it is proved that if A is a partial isometry such that either 0єW(A) or 0єW(An) for some positive integer n then A is unitary. Key words: Numerical range and unitary operator.
A robust method of estimating covariance matrix in multivariate data analysis
January 2010
We proposed a robust method of estimating covariance matrix in multivariate data set. The goal is to compare the proposed method with the most widely used robust methods (Minimum Volume Ellipsoid and Minimum Covariance Determinant) and the classical method (MLE) in detection of outliers at different levels and magnitude of outliers. The proposed robust method competes favourably well with both MVE and MCD and performed...
The efficiency of the linear classification rule in multi-group discriminant analysis
January 2010
A Monte Carlo study was performed to assess the relative efficiency of the linear classification rule in 2, 3 and 5-group discriminant analysis. The simulation design took into account the number of variables (4, 6, 10, and 18), the size sample so that: = 1.5, 2.5 and 5. Three values of the overlap, e of the populations were considered (0.05; 0.1; 0.15) and their common distribution was...
Reliability and economic analysis of 2-out-of-3 redundant system with priority to repair
December 2009
Two reliability models have been developed to compare some reliability and economic measures for a 2-out-of-3 redundant system having two original units (called standard units) and one duplicate unit which areinitially taken as spare in cold standby. The system is considered in up-state if any two of original and/or duplicate units are operative in parallel mode. The original unit is inspected at its...
Curve concentration for a singularly perturbed Neumann problem in three dimensional domain
December 2009
In this paper we consider the following problem where is a bounded domain in with smooth boundary, is a small parameter, denotes the outward normal of and . Let be a straight line intersecting with at exactly two points. We will prove the existence of a solution possessing curve concentrating set near , exponentially small in at any positive distance from the...
Visualizing the behaviour of reinforced concrete beam structure under various types of loadings
November 2009
This paper describes an approach to visualizing the detection of failure in Reinforced Concrete Beam Structure under various types of loadings. Several Reinforced Concrete Design (RCD) tools have been developed to support RCD, but there is little evidence that these solutions address the needs of the users. We studied RCD analysts’ daily activities in order to understand their routine work practices and...
Relative efficiency of non parametric error rate estimators in multi-group linear discriminant analysis
November 2009
A Monte Carlo study was achieved to assess the relative efficiency of ten non parametric error rate estimators in 2, 3 and 5-group linear discriminant analysis. The simulation design took into account the number ρ of variables (4, 6, 10, 18) together wit the size sample n so that: n/ρ = 1.5, 2.5 and 5. Three values of the overlap, e of the populations were...
A catastrophic-cum-restorative queuing model with correlated input for the cell traffic generated by new broadband services
November 2009
A Catastrophic-cum-Restorative Queuing Model has been developed for the cell traffic generated by New Broadband services. Transient analysis of the queuing model has been carried out. Some particular cases of the model have been derived and discussed. Key words: Catastrophes, correlation, broadband services, restoration.
Comparison of electron-plasmon scattering effect on low-field electron mobility in ZnO and SiC
October 2009
Iterative technique is used to solve Boltzmann transport equation for calculating temperature and doping dependencies of electron mobility in ZnO and SiC materials. The two-mode nature of the polar optic phonons is considered jointly with deformation potential acoustic, piezoelectric, ionized impurity and electron-plasmon scattering. Band non-parabolicity, admixture of p functions, arbitrary...
Cluster analysis of improved cassava varieties cultivated at Onne, Nigeria by the international institute of tropical agriculture
October 2009
Secondary data on proximate composition of “fufu” flour taken from forty three cassava mosaic disease (CMD) resistant varieties were used for this work. Agglomerative hierarchical cluster analysis was performed on the squared Euclidean distance matrix. The distance coefficients generated between the forty three CMD resistant varieties ranged from 0.000 to 89.120. Six (6) distinct groups were...
Enhanced data mining analysis in higher educational system using rough set theory
October 2009
One of the biggest challenges that higher education faces today is predicting the behavior of students. Institutions would like to know, something about the performances of the students group wise. Behrouz–Minaei-Bidgoli (2004) investigated a web based educational system using data mining techniques. He proposed a problem to investigate the performances of the students when the large data base of...
A dimension result for polar sets of Brownian path in n-spaces
September 2009
Let T(x,r) denote the occupation measure of the ball of radius r centered at x for Brownian motion {Xr},0 < t < 1 in Rn , n > 3. We consider the set and show that for a = 0,h(r) = r2 (logr)λ, λ > 1. Moreover, E0 n Ea = ø for a > 0. We deduce that the Hausdorff dimension of E0 is 2 for n > 3 Key words: Brownian motion, Hausdorff dimension,...
Causal relationship between gross domestic product and personal consumption expenditure of Nigeria
September 2009
This study employed regression analysis to investigate the casual relationship between gross domestic product and personal consumption expenditure of Nigeria using data from 1994 - 2007. A non insignificant value of 0.0514 was obtained as a slope coefficient indicating that an increase in gross domestic product has no significant effect on the personal consumption expenditure of Nigeria. This was further...
Adaptation of the preemptive handoff scheme in an integrated mobile communication environment
September 2009
A new preemptive handoff scheme in integrated mobile communication environment is presented in this paper. The preemptive handoff schemes have worked in such a way that data types of lesser priority have been preemptive in an ad-hoc fashion. In the proposed scheme, the cell is divided into two regions, the usable area and the handoff region. The right of preemption has been given to incoming handoff real-time...
Applications of soft computing techniques in materials engineering: A review
August 2009
Within the last two decades, a substantial amount of research efforts has been directed at the application of Soft Computing (SC) techniques in engineering. This paper provides a systematic review of the literature emanating from these efforts with particular focus on materials engineering. The primary aim is to provide background information, motivation for applications and an exposition to the methodologies...
On sandwich theorems of analytic functions involving Noor integral operator
August 2009
In this paper, we introduce sufficient conditions for subordination and superordination for subclass of analytic functions containing Noor integral operator. On the other hand, we prove the subordination and superordination results by some theorem studies and proofs. There are also obtained a sandwich results by different ways. Key words: Noor integral...
M|G|∞ queue system parameters for a particular collection of service time distributions
August 2009
The problems that arise in the computation of the moments of a particular collection of service time distributions, for which the M|G|∞ busy period and busy cycle become very easy to study, are presented in this paper. It is shown how to overcome them. The busy cycle renewal function, the “peak” and the “modified peak” for the M|G|∞ busy period and busy cycle in the case of...
Slip formulation for numerical simulations of jumping paratroopers
August 2009
The aim is to develop computational techniques for studying aerodynamic interactions between multiple objects when an object exits and separates from an aircraft. The object could be a paratrooper jumping out of a transport aircraft or a package of emergency aid dropped from a cargo plane. In all these cases, the computational challenge is to predict the dynamic behavior and path of the object, so that the...
Modeling laminar flow between a fixed impermeable disk and a porous rotating disk
August 2009
We formulate a mathematical model that governs operations of many engineering systems particularly the ceiling fan to explain the fluid flow between the fixed impermeable and the porous rotating disks. The model is based on the continuity and the Navier-Stokes equations which are reduced into a set of coupled ordinary differential equations through transformation by similarity variables. The coupled ordinary...
Graphics to fuzzy elements in appraisal of an in-house software based on inter-failure data analysis
July 2009
The performance of any software can be measured, approximately, by three parameters; Reliability, Availability and Maintainability. They provide information about the robustness of the software under consideration. In this work, a software is developed to computerize University of Ilorin student’s results and is designated as an IN-HOUSE Software. The formalism of fuzzy logic is used to investigate its...
Stability analysis of stochastic model of stock market price
July 2009
A stability analysis of stochastic model of price change at the floor of a stock market is considered. Precise conditions are obtained which determine the equilibrium price and growth rate of the stock shares in a particular case. In general, stability in a numerical procedure for the Black-Schole’s partial differential equation is established. An illustrative example is provided. Key...
Robustness of the maximum likelihood estimation procedure in factor analysis
June 2009
Random variables generated from five distributions were used to represent the common and specific factors in factor analysis in order to determine the robustness of the maximum likelihood estimation procedure. Five response variables were chosen for this study each with two factors. The chosen variables were transformed into linear combinations of an underlying set of hypothesized or unobserved components...
Statistical analysis of dependence structure of improved cassava varieties in Nigeria
June 2009
Multivariate methods were used to analyze a set of data on the proximate compositions of fufuflours processed from 43 different cassava mosaic disease (CMD) resistant varieties from National Root Crop Research Institute (NRCRT) Umudike Nigeria. The factor analysis reveals that three factors accounted for 77.8% of the total variables in the data. Factor 1 has eigenvalue of 3.082, factor 2 has an eigen...
A collocation multistep method for integrating ordinary differential equations on manifolds
May 2009
This paper concerns a family of generalized collocation multistep methods that evolves the numerical solution of ordinary differential equations on configuration spaces formulated as homogeneous manifolds. Collocating the general linear method at x = xx+k for k = 0,1,….s, , we obtain the discrete scheme which can be adapted to homogeneous spaces. Varying the values...
When does the pooled variance t-test fail?
May 2009
The pooled variance t-tests used prominently for comparing means between two groups is usually restricted with the assumptions of normality and homogeneity of variances. However, the violation of the assumptions happens in many real world data. In this study, the conditions where the pooled variance t-test would fail were investigated. The performance of the t-test was evaluated under different...
Application of variational iteration method to coupled system of nonlinear partial differential physical equations
May 2009
In this article 2 examples of the coupled system of nonlinear partial differential physical equations including diffusion-reaction equation have been investigated by means of variational iteration method which is a new numerical method for solving these types of equations. The results are presented finally in comparison with the exact solution, which show a good agreement and consistency with the exact...
A class of collocation methods for general second order ordinary differential equations
May 2009
In this paper, self starting hybrid block method of order (4,3,3)T is proposed for the solution of general second order initial value problem of the form Y” = f (x, y, y’) directly without reducing it to first systems of odes. The continuous formation of the integrator enable us to differentiate and evaluate at some grids and off-grid points to take care of...
Pre A*-Algebra as a Poset
May 2009
This paper is a study on algebraic structure of pre A*- algebra. We define center of a pre A*-algebra, B(A) = {x Î A/ x Ú x0/0 1} and prove that B(A) is a Boolean algebra. We define ordering relation on pre A*- algebra A by x ≤ y if yÙx = xÙy = x and prove that ≤ is a partial ordering on A and also find necessary conditions...
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