2008
32
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PULLBACK CROSSED MODULES OF ALGEBROIDS
2
2
In this paper, we present algebroids and crossed modules of algebroids. We also define pullbackcrossed module of algebroids.
1

1
5


M.
ALP
Dumlupinar University, Art and Science Faculty, Mathematics Department, Turkey
Dumlupinar University, Art and Science Faculty,
Turkey
malp@dumlupinar.edu.tr
Crossed module
algebroids
pullback
action
INVESTIGATION ON THE FLUXBASED TORQUERIPPLE BEHAVIOR IN DTC BASED INDUCTION MOTOR DRIVES
2
2
The efficiency of induction motors decreases at light loads. Efficiency optimizer control systemsadjust the motor flux value to achieve the best efficiency in a wide range of load variations. Reduced fluxoperation has some other benefits such as power factor improvement and torque ripple reduction. The latter isan important issue in a direct torque controlled induction motor drive. In this paper, the effect of fluxreference value on the torque ripple of a direct torque controlled induction motor is analyzed. The effect offlux value on torque ripple in a wide range of speed variations is investigated. Simulation and theexperimental results presented justify the validity of the theoretical analysis about torque ripple.
1

7
16


Sh
KABOLI
Electrical Engineering Department, Sharif University of Technology, Tehran, I. R. of Iran
Electrical Engineering Department, Sharif
Iran
kaboli@sharif.edu


M. R.
ZOLGHADRI
Electrical Engineering Department, Sharif University of Technology, Tehran, I. R. of Iran
Electrical Engineering Department, Sharif
Iran


S.
HAGHBIN
Electrical Engineering Department, Sharif University of Technology, Tehran, I. R. of Iran
Electrical Engineering Department, Sharif
Iran


P.
ESKANDARI
Electrical Engineering Department, Sharif University of Technology, Tehran, I. R. of Iran
Electrical Engineering Department, Sharif
Iran
Induction motor drive
direct torque control
torque ripple
predictive controller
CAPACITY ON FINSLER SPACES
2
2
Here, the concept of electric capacity on Finsler spaces is introduced and the fundamentalconformal invariant property is proved, i.e. the capacity of a compact set on a connected noncompact Finslermanifold is conformal invariant. This work enables mathematicians and theoretical physicists to become morefamiliar with the global Finsler geometry and one of its new applications.
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17
24


B.
BIDABAD
Faculty of Mathematics and Computer Sciences, Amirkabir University of Technology,
424 Hafez Ave, 15914 Tehran, I. R. of Iran
Faculty of Mathematics and Computer Sciences,
Iran
bidabad@aut.ac.ir


S.
HEDAYATIAN
Faculty of Mathematics and Computer Sciences, Chamran University of Ahvaz, Golestan Bld,
P.O. Box: 6135583151 Ahvaz, I. R. of Iran
Faculty of Mathematics and Computer Sciences,
Iran
Capacity
conformal invariant
Finsler space
INTEGRAL CHARACTERIZATIONS FOR TIMELIKE AND SPACELIKE CURVES ON THE LORENTZIAN SPHERE 3 S1
2
2
V. Dannon showed that spherical curves in E4 can be given by Frenetlike equations, and he thengave an integral characterization for spherical curves in E4 . In this paper, Lorentzian spherical timelike andspacelike curves in the space time 41 R are shown to be given by Frenetlike equations of timelike andspacelike curves in the Euclidean space E3 and the Minkowski 3space 31 R . Thus, finding an integralcharacterization for a Lorentzian spherical 41 R timelike and spacelike curve is identical to finding it for E3curves and 31 R timelike and spacelike curves. In the case of E3 curves, the integral characterizationcoincides with Dannon’s.Let {T, N, B}be the moving Frenet frame along the curve α (s) in the Minkowski space 31 R . Letα (s) be a unit speed C4 timelike (or spacelike) curve in 31 R so that α '(s) = T . Then, α (s) is a Frenetcurve with curvature κ (s) and torsion τ (s) if and only if there are constant vectors a and b so that(i) { [ ] } 0'( ) ( ) cos ( ) sin ( ) cos ( ) ( ) ( ) ( ) , s T s =κ s a ξ s + b ξ s + ∫ ξ s −ξ δ T δ κ δ dδ T is timelike,(ii) { ( ) } 0'( ) ( ) cosh ( ) ( ) ( ) ( ) s T s =κ s aeξ +be−ξ + ∫ ξ s −ξ δ T δ κ δ dδ , N is timelike,where0( ) ( ) . s ξ s = ∫ τ δ dδ
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25
31


M.
KAZAZ
Department of Mathematics, Faculty of Art and Sciences, University of Celal Bayar,
Muradiye Campus, 45047, Manisa, Turkey
Department of Mathematics, Faculty of Art
Turkey
mustafa.kazaz@bayar.edu.tr


H. H.
UGURLU
Gazi University, Gazi Faculty of Education, Department of Secondary Education, Science
and Mathematics Teaching, Mathematics Teaching Program, Ankara, Turkey
Gazi University, Gazi Faculty of Education,
Turkey


A.
OZDEMIR
Department of Mathematics, Faculty of Art and Sciences, University of Celal Bayar,
Muradiye Campus, 45047, Manisa, Turkey
Department of Mathematics, Faculty of Art
Turkey
Lorentzian 3sphere
Timelike curve
spacelike curve
curvature
DIRAC STRUCTURES
2
2
In this paper we introduce the concept of Dirac structures on (Hermitian) modules and vectorbundles and deduce some of their properties. Among other things we prove that there is a one to onecorrespondence between the set of all Dirac structures on a (Hermitian) module and the group of allautomorphisms of the module. This correspondence enables us to represent Dirac structures on (Hermitian)modules and on vector bundles in a very suitable form and define induced Dirac structures in a natural way.
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33
44


A.
SHAFIEI DEH ABAD
School of Mathematics, Statistics and Computer Science, University of Tehran, Tehran, I. R. of Iran
School of Mathematics, Statistics and Computer
Iran
shafiei@khayam.ut.ac.ir
Dirac structure
Hermitian module
Hilbert module
vector bundle
ON ENERGY DECAY OF AN NDIMENSIONAL THERMOELASTICITY SYSTEM WITH A NONLINEAR WEAK DAMPING
2
2
We study the exponential decay of global solution for an ndimensional thermoelasticity systemin a bounded domain of ℜn . By using the multiplier technique and constructing an energy functional welladapted to the system, the exponential decay is proved.
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45
51


F.
TAHAMTANI
Department of Mathematics, Shiraz University, Shiraz, I. R. of Iran
Department of Mathematics, Shiraz University,
Iran
tahamtani@susc.ac.ir
Thermoelasticity system
nonlinear weak damping
energy decay rate
CONFORMAL VECTOR FIELDS ON TANGENT BUNDLE WITH A SPECIAL LIFT FINSLER METRIC*
2
2
On a Finsler manifold, we define conformal vector fields and their complete lifts and prove that incertain conditions they are homothetic.
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53
59


E.
PEYGHAN
Department of Mathematics, Faculty of Science, University of Arak, Arak, I. R. of Iran
Department of Mathematics, Faculty of Science,
Iran
epeyghan@araku.ac.ir,


A.
RAZAVI
Department of Mathematics and Computer Science, Amirkabir University, Tehran, I. R. of Iran
Department of Mathematics and Computer Science,
Iran


A.
HEYDARI
Faculty of Science, Tarbiatmodares University, Tehran, I. R. of Iran
Faculty of Science, Tarbiatmodares University,
Iran
Conformal vector field
Complete lift
finsler manifold
lift metric
THE STRUCTURE OF DERIVATIONS FROM A FULL MATRIX ALGEBRA INTO ITS DUAL
2
2
Let A be a unital algebra over a field of characteristic zero. We show that every derivation from( ) n M A into its dual ( ) n M A ∗ is the sum of an inner derivation and a derivation induced by a derivationfrom A into A∗
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61
64


R.
ALIZADEH
Department of Mathematics, Shahed University, P. O. Box 18151159, Tehran, I. R. of Iran
Department of Mathematics, Shahed University,
Iran


H.
ESSLAMZADEH
Department of Mathematics, Shiraz University, Shiraz 71454, I. R. of Iran
Department of Mathematics, Shiraz University,
Iran
esslamz@shirazu.ac.ir
derivation
full matrix algebra
dual space
α − SEPARABLE AND OTOPOLOGICAL GROUP
2
2
We introduce some new concepts of topological spaces which say α − separable topologicalspace and Otopological group, α − first axiom, α − second axiom, and we find some relations betweenthem with some applications in normed spaces.
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65
70


K.
HAGHNEJAD AZAR
Department of Mathematics, Mohghegh Ardabili University, Ardabil, I. R. of Iran
Department of Mathematics, Mohghegh Ardabili
Iran
haghnejadmath@yahoo.com


A.
RIAZI
Faculty of Mathematics and Computer Science, Amir Kabir University Tehran, I. R. of Iran
Faculty of Mathematics and Computer Science,
Iran
Topological group
Otopological group
α − separable space
α − first axiom and α − second axiom
ON THE DISTRIBUTION OF ZSCORES
2
2
Let X ,..., Xn 1 be a random sample from a distribution with sample mean X and samplevariance S 2. In this paper we consider certain very general properties of the socalled “Zscores”X X S i n i ( − )/ : = 1,...., . A representation theorem is then given for Zscores obtained from an underlyingnormal population, together with a theorem for their limiting distribution as the sample size tends to infinity.Finally, two applications involving grading and testing for an outlier are presented.
1

71
78


J.
BEHBOODIAN
Department of Mathematics, Islamic Azad University, Shiraz, I. R. of Iran
Department of Mathematics, Islamic Azad University
Iran
behboodian@stat.susc.ac.ir,


A.
ASGHARZADEH
Department of Statistics, Faculty of Basic Sciences, Mazandaran University, Babolsar, I. R. of Iran
Department of Statistics, Faculty of Basic
Iran
Finite exchangeability
grading
outlier test
Quadratic Forms
Thompson's identity
Samuelson's inequality
Slutsky's theorem