Abstract: In this paper, the translation surfaces in 3-dimensional
Euclidean space generated by two space curves have been
investigated. It has been indicated that Scherk surface is not only
minimal translation surface.
Abstract: Tourism industry is an important sector in Malaysia economy and this motivates the examination of long-run relationships between tourist arrivals from three selected European countries in Malaysia and four possible determinants; relative prices, exchange rates, transportation cost and relative prices of substitute destination. The study utilizes data from January 1999 to September 2008 and employs standard econometric techniques that include unit root test and cointegration test. The estimated demand model indicates that depreciation of local currency and increases in prices at substitute destination have positive impact on tourist arrivals while increase in transportation cost has negative impact on tourist arrivals. In addition, the model suggests that higher rate of increase in local prices relative to prices at tourist country of origin may not deter tourists from coming to Malaysia
Abstract: In the present work, we introduce the particle swarm optimization called (PSO in short) to avoid the Runge-s phenomenon occurring in many numerical problems. This new approach is tested with some numerical examples including the generalized integral quadrature method in order to solve the Volterra-s integral equations
Abstract: The Euler-s equation of motion is extended to include
the viscosity stress tensor leading to the formulation of Navier–
Stokes type equation. The latter is linearized and applied to
investigate the rotational motion or vorticity in a viscous fluid.
Relations for the velocity of viscous waves and attenuation parameter
are obtained in terms of viscosity (μ) and the density (¤ü) of the fluid.
μ and ¤ü are measured experimentally as a function of temperature for
two different samples of light and heavy crude oil. These data
facilitated to determine the activation energy, velocity of viscous
wave and the attenuation parameter. Shear wave velocity in heavy oil
is found to be much larger than the light oil, whereas the attenuation
parameter in heavy oil is quite low in comparison to light one. The
activation energy of heavy oil is three times larger than light oil.
Abstract: The analytical solutions for geodesic acoustic
eigenmodes in tokamak plasmas with circular concentric magnetic
surfaces are found. In the frame of ideal magnetohydrodynamics the
dispersion relation taking into account the toroidal coupling between
electrostatic perturbations and electromagnetic perturbations with
poloidal mode number |m| = 2 is derived. In the absence of such
a coupling the dispersion relation gives the standard continuous
spectrum of geodesic acoustic modes. The analysis of the existence
of global eigenmodes for plasma equilibria with both off-axis
and on-axis maximum of the local geodesic acoustic frequency is
performed.
Abstract: In this paper, we present parallel alternating two-stage
methods for solving linear system Ax=b, where A is a symmetric
positive definite matrix. And we give some convergence results of
these methods for nonsingular linear system.
Abstract: In this paper, the semi–ratio–dependent predator-prey system with nonmonotonic functional response on time scales is investigated. By using the coincidence degree theory, sufficient conditions for existence of periodic solutions are obtained.
Abstract: This paper establishes some closed formulas for
Riemann- Liouville impulsive fractional integral calculus and also
for Riemann- Liouville and Caputo impulsive fractional
derivatives.
Abstract: This paper presents a spectroscopic study on doping
of Vanadyl pathalocyanine (VOPc) by [6,6]-phenyl C61 butyric acid
methyl ester (PCBM). The films are characterized by UV/Vis/NIR
spectroscopy. A drastic increase in the absorption coefficient has
been observed with increasing dopant concentration. Optical
properties of VOPc:PCBM films deposited by spin coating technique
were studied in detail. Optical band gap decreased with the PCBM
incorporation in the VOPc film. Optical band gap calculated from the
absorption spectra decreased from 3.32 eV to 3.26 eV with a
variation of 0–75 % of PCBM concentration in the VOPC films.
Abstract: The study on the tree growth for four species groups of commercial timber in Koh Kong province, Cambodia-s tropical rainforest is described. The simulation for these four groups had been successfully developed in the 5-year interval through year-60. Data were obtained from twenty permanent sample plots in the duration of thirteen years. The aim for this study was to develop stand table simulation system of tree growth by the species group. There were five steps involved in the development of the tree growth simulation: aggregate the tree species into meaningful groups by using cluster analysis; allocate the trees in the diameter classes by the species group; observe the diameter movement of the species group. The diameter growth rate, mortality rate and recruitment rate were calculated by using some mathematical formula. Simulation equation had been created by combining those parameters. Result showed the dissimilarity of the diameter growth among species groups.
Abstract: In this paper, the two-dimension differential transformation method (DTM) is employed to obtain the closed form solutions of the three famous coupled partial differential equation with physical interest namely, the coupled Korteweg-de Vries(KdV) equations, the coupled Burgers equations and coupled nonlinear Schrödinger equation. We begin by showing that how the differential transformation method applies to a linear and non-linear part of any PDEs and apply on these coupled PDEs to illustrate the sufficiency of the method for this kind of nonlinear differential equations. The results obtained are in good agreement with the exact solution. These results show that the technique introduced here is accurate and easy to apply.
Abstract: Buyer coalition with a combination of items is a group of buyers joining together to purchase a combination of items with a larger discount. The primary aim of existing buyer coalition with a combination of items research is to generate a large total discount. However, the aim is hard to achieve because this research is based on the assumption that each buyer completely knows other buyers- information or at least one buyer knows other buyers- information in a coalition by exchange of information. These assumption contrast with the real world environment where buyers join a coalition with incomplete information, i.e., they concerned only with their expected discounts. Therefore, this paper proposes a new buyer community coalition formation with a combination of items scheme, called the Community Compromised Combinatorial Coalition scheme, under such an environment of incomplete information. In order to generate a larger total discount, after buyers who want to join a coalition propose their minimum required saving, a coalition structure that gives a maximum total retail prices is formed. Then, the total discount division of the coalition is divided among buyers in the coalition depending on their minimum required saving and is a Pareto optimal. In mathematical analysis, we compare concepts of this scheme with concepts of the existing buyer coalition scheme. Our mathematical analysis results show that the total discount of the coalition in this scheme is larger than that in the existing buyer coalition scheme.
Abstract: Nonlinear propagation of ion-acoustic waves in a selfgravitating
dusty plasma consisting of warm positive ions,
isothermal two-temperature electrons and negatively charged dust
particles having charge fluctuations is studied using the reductive
perturbation method. It is shown that the nonlinear propagation of
ion-acoustic waves in such plasma can be described by an uncoupled
third order partial differential equation which is a modified form of
the usual Korteweg-deVries (KdV) equation. From this nonlinear
equation, a new type of solution for the ion-acoustic wave is
obtained. The effects of two-temperature electrons, gravity and dust
charge fluctuations on the ion-acoustic solitary waves are discussed
with possible applications.
Abstract: The problem of bin-packing in two dimensions (2BP) consists in placing a given set of rectangular items in a minimum number of rectangular and identical containers, called bins. This article treats the case of objects with a free orientation of 90Ôùª. We propose an approach of resolution combining optimization by colony of ants (ACO) and the heuristic method IMA to resolve this NP-Hard problem.
Abstract: The objective of the present work is to conduct
investigations leading to a more complete explanation of single phase
natural convective heat transfer in an enclosure with fin utilizing
nano fluids. The nano fluid used, which is composed of Aluminum
oxide nano particles in suspension of Ethylene glycol, is provided at
various volume fractions. The study is carried out numerically for a
range of Rayleigh numbers, fin heights and aspect ratio. The flow and
temperature distributions are taken to be two-dimensional. Regions
with the same velocity and temperature distributions are identified as
symmetry of sections. One half of such a rectangular region is chosen
as the computational domain taking into account the symmetry about
the fin. Transport equations are modeled by a stream functionvorticity
formulation and are solved numerically by finite-difference
schemes. Comparisons with previously published works on the basis
of special cases are done. Results are presented in the form of
streamline, vector and isotherm plots as well as the variation of local
Nusselt number along the fin under different conditions.
Abstract: Recent articles have addressed the problem to construct the confidence intervals for the mean of a normal distribution where the parameter space is restricted, see for example Wang [Confidence intervals for the mean of a normal distribution with restricted parameter space. Journal of Statistical Computation and Simulation, Vol. 78, No. 9, 2008, 829–841.], we derived, in this paper, analytic expressions of the coverage probability and the expected length of confidence interval for the normal mean when the whole parameter space is bounded. We also construct the confidence interval for the normal variance with restricted parameter for the first time and its coverage probability and expected length are also mathematically derived. As a result, one can use these criteria to assess the confidence interval for the normal mean and variance when the parameter space is restricted without the back up from simulation experiments.
Abstract: Feature selection is an important step in many pattern
classification problems. It is applied to select a subset of features,
from a much larger set, such that the selected subset is sufficient to
perform the classification task. Due to its importance, the problem of
feature selection has been investigated by many researchers. In this
paper, a novel feature subset search procedure that utilizes the Ant
Colony Optimization (ACO) is presented. The ACO is a
metaheuristic inspired by the behavior of real ants in their search for
the shortest paths to food sources. It looks for optimal solutions by
considering both local heuristics and previous knowledge. When
applied to two different classification problems, the proposed
algorithm achieved very promising results.
Abstract: The purpose of this note is to obtain some properties of
(∈,∈ ∨q)- fuzzy bi-ideals in a Γ-semigroup in order to characterize
regular and intra-regular Γ-semigroups.
Abstract: In this paper we introduce a new class of mg-continuous mapping and studied some of its basic properties.We obtain some characterizations of such functions. Moreover we define sub minimal structure and further study certain properties of mg-closed sets.
Abstract: We investigate an asymmetric connections model with a
dynamic network formation process, using an agent based simulation.
We permit heterogeneity of agents- value. Valuable persons seem
to have many links on real social networks. We focus on this
point of view, and examine whether valuable agents change the
structures of the terminal networks. Simulation reveals that valuable
agents diversify the terminal networks. We can not find evidence that
valuable agents increase the possibility that star networks survive the
dynamic process. We find that valuable agents disperse the degrees
of agents in each terminal network on an average.