2018-10-23T02:35:59Z
http://ijsts.shirazu.ac.ir/?_action=export&rf=summon&issue=465
Iranian Journal of Science and Technology (Sciences)
Transaction A: Science
1028-6276
1028-6276
2008
32
1
PULLBACK CROSSED MODULES OF ALGEBROIDS
M.
ALP
In this paper, we present algebroids and crossed modules of algebroids. We also define pullback<br />crossed module of algebroids.
Crossed module
algebroids
pullback
action
2008
02
17
1
5
http://ijsts.shirazu.ac.ir/article_2234_62c423d9a21fa541e8b88b608b5152fe.pdf
Iranian Journal of Science and Technology (Sciences)
Transaction A: Science
1028-6276
1028-6276
2008
32
1
INVESTIGATION ON THE FLUX-BASED TORQUE-RIPPLE BEHAVIOR IN DTC BASED INDUCTION MOTOR DRIVES
Sh
KABOLI
M. R.
ZOLGHADRI
S.
HAGHBIN
P.
ESKANDARI
The efficiency of induction motors decreases at light loads. Efficiency optimizer control systems<br />adjust the motor flux value to achieve the best efficiency in a wide range of load variations. Reduced flux<br />operation has some other benefits such as power factor improvement and torque ripple reduction. The latter is<br />an important issue in a direct torque controlled induction motor drive. In this paper, the effect of flux<br />reference value on the torque ripple of a direct torque controlled induction motor is analyzed. The effect of<br />flux value on torque ripple in a wide range of speed variations is investigated. Simulation and the<br />experimental results presented justify the validity of the theoretical analysis about torque ripple.
Induction motor drive
direct torque control
torque ripple
predictive controller
2008
02
17
7
16
http://ijsts.shirazu.ac.ir/article_2235_67e72585b39a8522188344db21f914fd.pdf
Iranian Journal of Science and Technology (Sciences)
Transaction A: Science
1028-6276
1028-6276
2008
32
1
CAPACITY ON FINSLER SPACES
B.
BIDABAD
S.
HEDAYATIAN
Here, the concept of electric capacity on Finsler spaces is introduced and the fundamental<br />conformal invariant property is proved, i.e. the capacity of a compact set on a connected non-compact Finsler<br />manifold is conformal invariant. This work enables mathematicians and theoretical physicists to become more<br />familiar with the global Finsler geometry and one of its new applications.
Capacity
conformal invariant
Finsler space
2008
02
17
17
24
http://ijsts.shirazu.ac.ir/article_2237_c853a94eb7e70ca1fcffe2b37e5b1eee.pdf
Iranian Journal of Science and Technology (Sciences)
Transaction A: Science
1028-6276
1028-6276
2008
32
1
INTEGRAL CHARACTERIZATIONS FOR TIMELIKE AND SPACELIKE CURVES ON THE LORENTZIAN SPHERE 3 S1
M.
KAZAZ
H. H.
UGURLU
A.
OZDEMIR
V. Dannon showed that spherical curves in E4 can be given by Frenet-like equations, and he then<br />gave an integral characterization for spherical curves in E4 . In this paper, Lorentzian spherical timelike and<br />spacelike curves in the space time 4<br />1 R are shown to be given by Frenet-like equations of timelike and<br />spacelike curves in the Euclidean space E3 and the Minkowski 3-space 3<br />1 R . Thus, finding an integral<br />characterization for a Lorentzian spherical 4<br />1 R -timelike and spacelike curve is identical to finding it for E3<br />curves and 3<br />1 R -timelike and spacelike curves. In the case of E3 curves, the integral characterization<br />coincides with Dannon’s.<br />Let {T, N, B}be the moving Frenet frame along the curve α (s) in the Minkowski space 3<br />1 R . Let<br />α (s) be a unit speed C4 -timelike (or spacelike) curve in 3<br />1 R so that α '(s) = T . Then, α (s) is a Frenet<br />curve with curvature κ (s) and torsion τ (s) if and only if there are constant vectors a and b so that<br />(i) { [ ] } 0<br />'( ) ( ) 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,<br />(ii) { ( ) } 0<br />'( ) ( ) cosh ( ) ( ) ( ) ( ) s T s =κ s aeξ +be−ξ + ∫ ξ s −ξ δ T δ κ δ dδ , N is timelike,<br />where<br />0<br />( ) ( ) . s ξ s = ∫ τ δ dδ
Lorentzian 3-sphere
Timelike curve
spacelike curve
curvature
2008
02
17
25
31
http://ijsts.shirazu.ac.ir/article_2238_9ccf89393e0c615c0234b48509b20d4e.pdf
Iranian Journal of Science and Technology (Sciences)
Transaction A: Science
1028-6276
1028-6276
2008
32
1
DIRAC STRUCTURES
A.
SHAFIEI DEH ABAD
In this paper we introduce the concept of Dirac structures on (Hermitian) modules and vector<br />bundles and deduce some of their properties. Among other things we prove that there is a one to one<br />correspondence between the set of all Dirac structures on a (Hermitian) module and the group of all<br />automorphisms of the module. This correspondence enables us to represent Dirac structures on (Hermitian)<br />modules and on vector bundles in a very suitable form and define induced Dirac structures in a natural way.
Dirac structure
Hermitian module
Hilbert module
vector bundle
2008
02
17
33
44
http://ijsts.shirazu.ac.ir/article_2239_ec8e645e2e54512fcf6f5038521f36fe.pdf
Iranian Journal of Science and Technology (Sciences)
Transaction A: Science
1028-6276
1028-6276
2008
32
1
ON ENERGY DECAY OF AN N-DIMENSIONAL THERMOELASTICITY SYSTEM WITH A NONLINEAR WEAK DAMPING
F.
TAHAMTANI
We study the exponential decay of global solution for an n-dimensional thermo-elasticity system<br />in a bounded domain of ℜn . By using the multiplier technique and constructing an energy functional well<br />adapted to the system, the exponential decay is proved.
Thermo-elasticity system
non-linear weak damping
energy decay rate
2008
02
17
45
51
http://ijsts.shirazu.ac.ir/article_2240_6be2e046e60631ea1bf828a2a5179ccd.pdf
Iranian Journal of Science and Technology (Sciences)
Transaction A: Science
1028-6276
1028-6276
2008
32
1
CONFORMAL VECTOR FIELDS ON TANGENT BUNDLE WITH A SPECIAL LIFT FINSLER METRIC*
E.
PEYGHAN
A.
RAZAVI
A.
HEYDARI
On a Finsler manifold, we define conformal vector fields and their complete lifts and prove that in<br />certain conditions they are homothetic.
Conformal vector field
Complete lift
finsler manifold
lift metric
2008
02
17
53
59
http://ijsts.shirazu.ac.ir/article_2242_a7a4b6fb2c6283dfb292f9e29ed1cc7f.pdf
Iranian Journal of Science and Technology (Sciences)
Transaction A: Science
1028-6276
1028-6276
2008
32
1
THE STRUCTURE OF DERIVATIONS FROM A FULL MATRIX ALGEBRA INTO ITS DUAL
R.
ALIZADEH
H.
ESSLAMZADEH
Let A be a unital algebra over a field of characteristic zero. We show that every derivation from<br />( ) n M A into its dual ( ) n M A ∗ is the sum of an inner derivation and a derivation induced by a derivation<br />from A into A∗
derivation
full matrix algebra
dual space
2008
02
17
61
64
http://ijsts.shirazu.ac.ir/article_2243_75889e97656d745af5ba0a1ac3c67c89.pdf
Iranian Journal of Science and Technology (Sciences)
Transaction A: Science
1028-6276
1028-6276
2008
32
1
α − SEPARABLE AND O-TOPOLOGICAL GROUP
K.
HAGHNEJAD AZAR
A.
RIAZI
We introduce some new concepts of topological spaces which say α − separable topological<br />space and O-topological group, α − first axiom, α − second axiom, and we find some relations between<br />them with some applications in normed spaces.
Topological group
O-topological group
α − separable space
α − first axiom and α − second axiom
2008
02
17
65
70
http://ijsts.shirazu.ac.ir/article_2244_96cf814894c4986d8503ec748d4bbf73.pdf
Iranian Journal of Science and Technology (Sciences)
Transaction A: Science
1028-6276
1028-6276
2008
32
1
ON THE DISTRIBUTION OF Z-SCORES
J.
BEHBOODIAN
A.
ASGHARZADEH
Let X ,..., Xn 1 be a random sample from a distribution with sample mean X and sample<br />variance S 2. In this paper we consider certain very general properties of the so-called “Z-scores”<br />X X S i n i ( − )/ : = 1,...., . A representation theorem is then given for Z-scores obtained from an underlying<br />normal population, together with a theorem for their limiting distribution as the sample size tends to infinity.<br />Finally, two applications involving grading and testing for an outlier are presented.
Finite exchangeability
grading
outlier test
Quadratic Forms
Thompson's identity
Samuelson's
inequality
Slutsky's theorem
2008
02
17
71
78
http://ijsts.shirazu.ac.ir/article_2245_7c4086e2bf5cb1aaec28c2c0824b1b6e.pdf