Iranian Journal of Electrical & Electronic Engineering
http://ijeee.iust.ac.ir
Iranian Journal of Electrical and Electronic Engineering - Journal articles for year 2005, Volume 1, Number 1Yektaweb Collection - http://www.yektaweb.comen2005/1/12A generalized ABFT technique using a fault tolerant neural network
http://ijeee.iust.ac.ir/browse.php?a_id=38&sid=1&slc_lang=en
In this paper we first show that standard BP algorithm cannot yeild to a uniform
information distribution over the neural network architecture. A measure of sensitivity is
defined to evaluate fault tolerance of neural network and then we show that the sensitivity
of a link is closely related to the amount of information passes through it. Based on this
assumption, we prove that the distribution of output error caused by s-a-0 (stuck at 0) faults
in a MLP network has a Gaussian distribution function. UDBP (Uniformly Distributed
Back Propagation) algorithm is then introduced to minimize mean and variance of the
output error. Simulation results show that UDBP has the least sensitivity and the highest
fault tolerance among other algorithms such as WRTA, N-FTBP and ADP. Then a MLP
neural network trained with UDBP, contributes in an Algorithm Based Fault Tolerant
(ABFT) scheme to protect a nonlinear data process block. The neural network is trained to
produce an all zero syndrome sequence in the absence of any faults. A systematic real
convolution code guarantees that faults representing errors in the processed data will result
in notable nonzero values in syndrome sequence. A majority logic decoder can easily detect
and correct single faults by observing the syndrome sequence. Simulation results
demonstrating the error detection and correction behavior against random s-a-0 faults are
presented too. A. MoosavieniaSubspace system identification
http://ijeee.iust.ac.ir/browse.php?a_id=39&sid=1&slc_lang=en
We give a general overview of the state-of-the-art in subspace system
identification methods. We have restricted ourselves to the most important ideas and
developments since the methods appeared in the late eighties. First, the basis of linear
subspace identification are summarized. Different algorithms one finds in literature (Such
as N4SID, MOESP, CVA) are discussed and put into a unifying framework. Further, a
comparison between subspace identification and prediction error methods is made on the
basis of computational complexity and precision of methods by applying them to a glass
tube manufacturing process. J. PoshtanImplementation of an adaptive burst DQPSK receiver over shallow water acoustic channel
http://ijeee.iust.ac.ir/browse.php?a_id=40&sid=1&slc_lang=en
In an environment such as underwater channel where placing test equipments are
difficult to handle, it is much practical to have hardware simulators to examine suitably
designed transceivers (transmitter/receiver). The simulators of this kind will then allow
researchers to observe their intentions and carry out repetitive tests to find suitable digital
coding/decoding algorithms.
In this paper, a simplified shallow water digital data transmission system is first introduced.
The transmission channel considered here is a stochastic DSP hardware model in which
signal degradations leads to a severe distortion in phase and amplitude (fades) across the
bandwidth of the received signal. A computer base-band channel model with frequency
non-selective feature is derived by the authors [10-11]. This system was based on fullraised
cosine channel modelling and proved to be the most suitable for vertical and shortrange
underwater communication csdfher), with a reflected path (specula component, when
the acoustic hydrophone receives reflected signals from surface and bottom of the sea) and
a random path (diffused component, when the acoustic hydrophone receives scattered
signals from the volume of the sea). The model assumed perfect transmitter-receiver
synchronization but utilized realistic channel time delays, and demonstrated the timevarying
characteristics of an underwater acoustic channel observed in practice. In this
paper, they are used to provide a full system simulation in order to design an adaptive
receiver employing the most advanced digital signal processing techniques in hardware to
predict realizable error performances.A new fuzzy-based maximum power point tracker for photovoltaic applications
http://ijeee.iust.ac.ir/browse.php?a_id=41&sid=1&slc_lang=en
A new fuzzy maximum power point tracker (MPPT) for photovoltaic systems is
proposed. Fuzzy controller input parameters dI dP , ) dI dP ( D and variation of duty cycle
( DC D ) are used to generate the optimal MPPT converter duty cycle, such that solar panel
maximum power is generated under different operating conditions. A photovoltaic system
including a solar panel, a fuzzy MPP tracker and a resistive load is designed, simulated and
constructed. The fuzzy MPP tracker includes a buck dc/dc converter, fuzzy controller and
interfacing circuits. Theoretical and experimental results are used to indicate the advantages
and limitations of the proposed technique. M. A. S. MasoumAltitude measurement using laser beam reflected from water surface
http://ijeee.iust.ac.ir/browse.php?a_id=42&sid=1&slc_lang=en
In this paper altitude measurement from water surface using laser beam is
presented. Research data indicate that the reflection of infrared waves from water surface is
about zero and it is less than 2% for visible radiations. Phase-shift and heterodyne
technique was used for the measurement, and the laser beam ( mW p nm 10 , 700 = = l ) was
modulated by a sine wave having a fixed frequency. The optimum design and low-noise
elements made it possible to detect a light power about 20 nW at operating frequency. Sh. Mohammad NejadReduced order model for doubly output induction generator in wind park using integral manifold theory
http://ijeee.iust.ac.ir/browse.php?a_id=44&sid=1&slc_lang=en
A dynamic reduced order model using integral manifold theory has been derived,
which can be used to simulate the DOIG wind turbine using a double-winding
representation of the generator rotor. The model is suitable for use in transient stability
programs that can be used to investigate large power systems. The behavior of a wind farm
and the network under various system disturbances was studied using this dynamic model.
Simulation results of the proposed method represents that integral manifold method results
fit the detailed model results with a higher precision than other methods. M. Kalantar