ORIGINAL_ARTICLE
PULLBACK CROSSED MODULES OF ALGEBROIDS
In this paper, we present algebroids and crossed modules of algebroids. We also define pullbackcrossed module of algebroids.
https://ijsts.shirazu.ac.ir/article_2234_62c423d9a21fa541e8b88b608b5152fe.pdf
2008-02-17
1
5
10.22099/ijsts.2008.2234
Crossed module
algebroids
pullback
Action
M.
ALP
malp@dumlupinar.edu.tr
1
Dumlupinar University, Art and Science Faculty, Mathematics Department, Turkey
LEAD_AUTHOR
ORIGINAL_ARTICLE
INVESTIGATION ON THE FLUX-BASED TORQUE-RIPPLE BEHAVIOR IN DTC BASED INDUCTION MOTOR DRIVES
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.
https://ijsts.shirazu.ac.ir/article_2235_67e72585b39a8522188344db21f914fd.pdf
2008-02-17
7
16
10.22099/ijsts.2008.2235
Induction motor drive
direct torque control
torque ripple
predictive controller
Sh
KABOLI
kaboli@sharif.edu
1
Electrical Engineering Department, Sharif University of Technology, Tehran, I. R. of Iran
LEAD_AUTHOR
M. R.
ZOLGHADRI
2
Electrical Engineering Department, Sharif University of Technology, Tehran, I. R. of Iran
AUTHOR
S.
HAGHBIN
3
Electrical Engineering Department, Sharif University of Technology, Tehran, I. R. of Iran
AUTHOR
P.
ESKANDARI
4
Electrical Engineering Department, Sharif University of Technology, Tehran, I. R. of Iran
AUTHOR
ORIGINAL_ARTICLE
CAPACITY ON FINSLER SPACES
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 non-compact 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.
https://ijsts.shirazu.ac.ir/article_2237_c853a94eb7e70ca1fcffe2b37e5b1eee.pdf
2008-02-17
17
24
10.22099/ijsts.2008.2237
Capacity
conformal invariant
Finsler space
B.
BIDABAD
bidabad@aut.ac.ir
1
Faculty of Mathematics and Computer Sciences, Amirkabir University of Technology, 424 Hafez Ave, 15914 Tehran, I. R. of Iran
LEAD_AUTHOR
S.
HEDAYATIAN
2
Faculty of Mathematics and Computer Sciences, Chamran University of Ahvaz, Golestan Bld, P.O. Box: 61355-83151 Ahvaz, I. R. of Iran
AUTHOR
ORIGINAL_ARTICLE
INTEGRAL CHARACTERIZATIONS FOR TIMELIKE AND SPACELIKE CURVES ON THE LORENTZIAN SPHERE 3 S1
V. Dannon showed that spherical curves in E4 can be given by Frenet-like 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 Frenet-like equations of timelike andspacelike curves in the Euclidean space E3 and the Minkowski 3-space 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
https://ijsts.shirazu.ac.ir/article_2238_9ccf89393e0c615c0234b48509b20d4e.pdf
2008-02-17
25
31
10.22099/ijsts.2008.2238
Lorentzian 3-sphere
Timelike curve
spacelike curve
curvature
M.
KAZAZ
mustafa.kazaz@bayar.edu.tr
1
Department of Mathematics, Faculty of Art and Sciences, University of Celal Bayar, Muradiye Campus, 45047, Manisa, Turkey
LEAD_AUTHOR
H. H.
UGURLU
2
Gazi University, Gazi Faculty of Education, Department of Secondary Education, Science and Mathematics Teaching, Mathematics Teaching Program, Ankara, Turkey
AUTHOR
A.
OZDEMIR
3
Department of Mathematics, Faculty of Art and Sciences, University of Celal Bayar, Muradiye Campus, 45047, Manisa, Turkey
AUTHOR
ORIGINAL_ARTICLE
DIRAC STRUCTURES
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.
https://ijsts.shirazu.ac.ir/article_2239_ec8e645e2e54512fcf6f5038521f36fe.pdf
2008-02-17
33
44
10.22099/ijsts.2008.2239
Dirac structure
Hermitian module
Hilbert module
vector bundle
A.
SHAFIEI DEH ABAD
shafiei@khayam.ut.ac.ir
1
School of Mathematics, Statistics and Computer Science, University of Tehran, Tehran, I. R. of Iran
LEAD_AUTHOR
ORIGINAL_ARTICLE
ON ENERGY DECAY OF AN N-DIMENSIONAL THERMOELASTICITY SYSTEM WITH A NONLINEAR WEAK DAMPING
We study the exponential decay of global solution for an n-dimensional thermo-elasticity 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.
https://ijsts.shirazu.ac.ir/article_2240_6be2e046e60631ea1bf828a2a5179ccd.pdf
2008-02-17
45
51
10.22099/ijsts.2008.2240
Thermo-elasticity system
non-linear weak damping
energy decay rate
F.
TAHAMTANI
tahamtani@susc.ac.ir
1
Department of Mathematics, Shiraz University, Shiraz, I. R. of Iran
LEAD_AUTHOR
ORIGINAL_ARTICLE
CONFORMAL VECTOR FIELDS ON TANGENT BUNDLE WITH A SPECIAL LIFT FINSLER METRIC*
On a Finsler manifold, we define conformal vector fields and their complete lifts and prove that incertain conditions they are homothetic.
https://ijsts.shirazu.ac.ir/article_2242_a7a4b6fb2c6283dfb292f9e29ed1cc7f.pdf
2008-02-17
53
59
10.22099/ijsts.2008.2242
Conformal vector field
Complete lift
finsler manifold
lift metric
E.
PEYGHAN
e-peyghan@araku.ac.ir,
1
Department of Mathematics, Faculty of Science, University of Arak, Arak, I. R. of Iran
LEAD_AUTHOR
A.
RAZAVI
2
Department of Mathematics and Computer Science, Amirkabir University, Tehran, I. R. of Iran
AUTHOR
A.
HEYDARI
3
Faculty of Science, Tarbiatmodares University, Tehran, I. R. of Iran
AUTHOR
ORIGINAL_ARTICLE
THE STRUCTURE OF DERIVATIONS FROM A FULL MATRIX ALGEBRA INTO ITS DUAL
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∗
https://ijsts.shirazu.ac.ir/article_2243_75889e97656d745af5ba0a1ac3c67c89.pdf
2008-02-17
61
64
10.22099/ijsts.2008.2243
derivation
full matrix algebra
dual space
R.
ALIZADEH
1
Department of Mathematics, Shahed University, P. O. Box 18151-159, Tehran, I. R. of Iran
AUTHOR
H.
ESSLAMZADEH
esslamz@shirazu.ac.ir
2
Department of Mathematics, Shiraz University, Shiraz 71454, I. R. of Iran
LEAD_AUTHOR
ORIGINAL_ARTICLE
α − SEPARABLE AND O-TOPOLOGICAL GROUP
We introduce some new concepts of topological spaces which say α − separable topologicalspace and O-topological group, α − first axiom, α − second axiom, and we find some relations betweenthem with some applications in normed spaces.
https://ijsts.shirazu.ac.ir/article_2244_96cf814894c4986d8503ec748d4bbf73.pdf
2008-02-17
65
70
10.22099/ijsts.2008.2244
Topological group
O-topological group
α − separable space
α − first axiom and α − second axiom
K.
HAGHNEJAD AZAR
haghnejadmath@yahoo.com
1
Department of Mathematics, Mohghegh Ardabili University, Ardabil, I. R. of Iran
LEAD_AUTHOR
A.
RIAZI
2
Faculty of Mathematics and Computer Science, Amir Kabir University Tehran, I. R. of Iran
AUTHOR
ORIGINAL_ARTICLE
ON THE DISTRIBUTION OF Z-SCORES
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 so-called “Z-scores”X X S i n i ( − )/ : = 1,...., . A representation theorem is then given for Z-scores 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.
https://ijsts.shirazu.ac.ir/article_2245_7c4086e2bf5cb1aaec28c2c0824b1b6e.pdf
2008-02-17
71
78
10.22099/ijsts.2008.2245
Finite exchangeability
grading
outlier test
Quadratic Forms
Thompson's identity
Samuelson's
inequality
Slutsky's theorem
J.
BEHBOODIAN
behboodian@stat.susc.ac.ir,
1
Department of Mathematics, Islamic Azad University, Shiraz, I. R. of Iran
LEAD_AUTHOR
A.
ASGHARZADEH
2
Department of Statistics, Faculty of Basic Sciences, Mazandaran University, Babolsar, I. R. of Iran
AUTHOR