Abstract: In this paper, we analyze and test a scheme for the
estimation of electrical fundamental frequency signals from the
harmonic load current and voltage signals.
The scheme was based on using two different Multi Layer
Artificial Neural Networks (ML-ANN) one for the current and the
other for the voltage.
This study also analyzes and tests the effect of choosing the
optimum artificial neural networks- sizes which determine the quality
and accuracy of the estimation of electrical fundamental frequency
signals.
The simulink tool box of the Matlab program for the simulation of
the test system and the test of the neural networks has been used.
Abstract: In this research, effect of combustion reaction
mechanism on direct initiation of detonation has been studied
numerically. For this purpose, reaction mechanism has been
simulated by using a three-step chemical kinetics model. The reaction
scheme consists sequentially of a chain-initiation and chainbranching
step, followed by a temperature -independent chaintermination.
In a previous research, the effect of chain-branching on
the direct initiation of detonation is studied. In this research effect of
chain-initiation on direct initiation of detonation is investigated. For
the investigation, first a characteristic time (τ) for each step of
mechanism, which includes effect of different kinetics parameters, is
defined. Then the effect of characteristic time of chain-initiation (τI)
on critical initiation energy is studied. It is seen that increasing τI,
causes critical initiation energy to be increased. Drawing detonation's
shock pressure diagrams for different cases, shows that in small value
of τI , kinetics has more important effect on the behavior of the wave.
Abstract: One of the approaches enabling people with amputated
limbs to establish some sort of interface with the real world includes
the utilization of the myoelectric signal (MES) from the remaining
muscles of those limbs. The MES can be used as a control input to a
multifunction prosthetic device. In this control scheme, known as the
myoelectric control, a pattern recognition approach is usually utilized
to discriminate between the MES signals that belong to different
classes of the forearm movements. Since the MES is recorded using
multiple channels, the feature vector size can become very large. In
order to reduce the computational cost and enhance the generalization
capability of the classifier, a dimensionality reduction method is
needed to identify an informative yet moderate size feature set. This
paper proposes a new fuzzy version of the well known Fisher-s
Linear Discriminant Analysis (LDA) feature projection technique.
Furthermore, based on the fact that certain muscles might contribute
more to the discrimination process, a novel feature weighting scheme
is also presented by employing Particle Swarm Optimization (PSO)
for estimating the weight of each feature. The new method, called
PSOFLDA, is tested on real MES datasets and compared with other
techniques to prove its superiority.
Abstract: A pressure-based implicit procedure to solve Navier-
Stokes equations on a nonorthogonal mesh with collocated finite
volume formulation is used to simulate flow around the smart and
conventional flaps of spoiler under the ground effect. Cantilever
beam with uniformly varying load with roller support at the free end
is considered for smart flaps. The boundedness criteria for this
procedure are determined from a Normalized Variable diagram
(NVD) scheme. The procedure incorporates es the k -ε eddyviscosity
turbulence model. The method is first validated against
experimental data. Then, the algorithm is applied for turbulent
aerodynamic flows around a spoiler section with smart and
conventional flaps for different attack angle, flap angle and ground
clearance where the results of two flaps are compared.
Abstract: Information hiding for authenticating and verifying the content integrity of the multimedia has been exploited extensively in the last decade. We propose the idea of using genetic algorithm and non-deterministic dependence by involving the un-watermarkable coefficients for digital image authentication. Genetic algorithm is used to intelligently select coefficients for watermarking in a DCT based image authentication scheme, which implicitly watermark all the un-watermarkable coefficients also, in order to thwart different attacks. Experimental results show that such intelligent selection results in improvement of imperceptibility of the watermarked image, and implicit watermarking of all the coefficients improves security against attacks such as cover-up, vector quantization and transplantation.
Abstract: The global chaos synchronization for a class of time-delayed power systems is investigated via observer-based approach. By employing the concepts of quadratic stability theory and generalized system model, a new sufficient criterion for constructing an observer is deduced. In contrast to the previous works, this paper proposes a theoretical and systematic design procedure to realize chaos synchronization for master-slave power systems. Finally, an illustrative example is given to show the applicability of the obtained scheme.
Abstract: We propose a control design scheme that aims to
prevent undesirable liquid outpouring and suppress sloshing during
the forward and backward tilting phases of the pouring process, for
the case of liquid containers carried by manipulators. The proposed
scheme combines a partial inverse dynamics controller with a PID
controller, tuned with the use of a “metaheuristic" search algorithm.
The “metaheuristic" search algorithm tunes the PID controller based
on simulation results of the plant-s linearization around the operating
point corresponding to the critical tilting angle, where outpouring
initiates. Liquid motion is modeled using the well-known pendulumtype
model. However, the proposed controller does not require
measurements of the liquid-s motion within the tank.
Abstract: The frequency contents of the non-stationary
signals vary with time. For proper characterization of such
signals, a smart time-frequency representation is necessary.
Classically, the STFT (short-time Fourier transform) is
employed for this purpose. Its limitation is the fixed timefrequency
resolution. To overcome this drawback an enhanced
STFT version is devised. It is based on the signal driven
sampling scheme, which is named as the cross-level sampling.
It can adapt the sampling frequency and the window function
(length plus shape) by following the input signal local
variations. This adaptation results into the proposed technique
appealing features, which are the adaptive time-frequency
resolution and the computational efficiency.
Abstract: The use of the mechanical simulation (in particular the finite element analysis) requires the management of assumptions in order to analyse a real complex system. In finite element analysis (FEA), two modeling steps require assumptions to be able to carry out the computations and to obtain some results: the building of the physical model and the building of the simulation model. The simplification assumptions made on the analysed system in these two steps can generate two kinds of errors: the physical modeling errors (mathematical model, domain simplifications, materials properties, boundary conditions and loads) and the mesh discretization errors. This paper proposes a mesh adaptive method based on the use of an h-adaptive scheme in combination with an error estimator in order to choose the mesh of the simulation model. This method allows us to choose the mesh of the simulation model in order to control the cost and the quality of the finite element analysis.
Abstract: This paper is a numerical investigation of a laminar
isothermal plane two dimensional wall jet. Special attention has been
paid to the effect of the inlet conditions at the nozzle exit on the
hydrodynamic and thermal characteristics of the flow. The
behaviour of various fluids evolving in both forced and mixed
convection regimes near a vertical plate plane is carried out. The
system of governing equations is solved with an implicit finite
difference scheme. For numerical stability we use a staggered non
uniform grid. The obtained results show that the effect of the Prandtl
number is significant in the plume region in which the jet flow is
governed by buoyant forces. Further for ascending X values, the
buoyancy forces become dominating, and a certain agreement
between the temperature profiles are observed, which shows that the
velocity profile has no longer influence on the wall temperature
evolution in this region. Fluids with low Prandtl number warm up
more importantly, because for such fluids the effect of heat diffusion
is higher.
Abstract: In this work, we present an automatic vehicle detection
system for airborne videos using combined features. We propose a
pixel-wise classification method for vehicle detection using Dynamic
Bayesian Networks. In spite of performing pixel-wise classification,
relations among neighboring pixels in a region are preserved in the
feature extraction process. The main novelty of the detection scheme is
that the extracted combined features comprise not only pixel-level
information but also region-level information. Afterwards, tracking is
performed on the detected vehicles. Tracking is performed using
efficient Kalman filter with dynamic particle sampling. Experiments
were conducted on a wide variety of airborne videos. We do not
assume prior information of camera heights, orientation, and target
object sizes in the proposed framework. The results demonstrate
flexibility and good generalization abilities of the proposed method on
a challenging dataset.
Abstract: Texture classification is an important image processing
task with a broad application range. Many different techniques for
texture classification have been explored. Using sparse approximation
as a feature extraction method for texture classification is a relatively
new approach, and Skretting et al. recently presented the Frame
Texture Classification Method (FTCM), showing very good results on
classical texture images. As an extension of that work the FTCM is
here tested on a real world application as detection of abnormalities
in mammograms. Some extensions to the original FTCM that are
useful in some applications are implemented; two different smoothing
techniques and a vector augmentation technique. Both detection of
microcalcifications (as a primary detection technique and as a last
stage of a detection scheme), and soft tissue lesions in mammograms
are explored. All the results are interesting, and especially the results
using FTCM on regions of interest as the last stage in a detection
scheme for microcalcifications are promising.
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: 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: In this paper by using the port-controlled Hamiltonian
(PCH) systems theory, a full-order nonlinear controlled model is first
developed. Then a nonlinear passivity-based robust adaptive control
(PBRAC) of switched reluctance motor in the presence of external
disturbances for the purpose of torque ripple reduction and
characteristic improvement is presented. The proposed controller
design is separated into the inner loop and the outer loop controller.
In the inner loop, passivity-based control is employed by using
energy shaping techniques to produce the proper switching function.
The outer loop control is employed by robust adaptive controller to
determine the appropriate Torque command. It can also overcome the
inherent nonlinear characteristics of the system and make the whole
system robust to uncertainties and bounded disturbances. A 4KW 8/6
SRM with experimental characteristics that takes magnetic saturation
into account is modeled, simulation results show that the proposed
scheme has good performance and practical application prospects.
Abstract: To support user mobility for a wireless network new mechanisms are needed and are fundamental, such as paging, location updating, routing, and handover. Also an important key feature is mobile QoS offered by the WATM. Several ATM network protocols should be updated to implement mobility management and to maintain the already ATM QoS over wireless ATM networks. A survey of the various schemes and types of handover is provided. Handover procedure allows guarantee the terminal connection reestablishment when it moves between areas covered by different base stations. It is useful to satisfy user radio link transfer without interrupting a connection. However, failure to offer efficient solutions will result in handover important packet loss, severe delays and degradation of QoS offered to the applications. This paper reviews the requirements, characteristics and open issues of wireless ATM, particularly with regard to handover. It introduces key aspects of WATM and mobility extensions, which are added in the fixed ATM network. We propose a flexible approach for handover management that will minimize the QoS deterioration. Functional entities of this flexible approach are discussed in order to achieve minimum impact on the connection quality when a MT crosses the BS.
Abstract: This paper presents the approach to design the Auto-
Tuning PID controller for interactive Water Level Process using
integral step response. The Integral Step Response (ISR) is the
method to model a dynamic process which can be done easily,
conveniently and very efficiently. Therefore this method is advantage
for design the auto tune PID controller. Our scheme uses the root
locus technique to design PID controller. In this paper MATLAB is
used for modeling and testing of the control system. The
experimental results of the interacting water level process can be
satisfyingly illustrated the transient response and the steady state
response.
Abstract: Through 1980s, management accounting researchers
described the increasing irrelevance of traditional control and
performance measurement systems. The Balanced Scorecard (BSC)
is a critical business tool for a lot of organizations. It is a
performance measurement system which translates mission and
strategy into objectives. Strategy map approach is a development
variant of BSC in which some necessary causal relations must be
established. To recognize these relations, experts usually use
experience. It is also possible to utilize regression for the same
purpose. Structural Equation Modeling (SEM), which is one of the
most powerful methods of multivariate data analysis, obtains more
appropriate results than traditional methods such as regression. In the
present paper, we propose SEM for the first time to identify the
relations between objectives in the strategy map, and a test to
measure the importance of relations. In SEM, factor analysis and test
of hypotheses are done in the same analysis. SEM is known to be
better than other techniques at supporting analysis and reporting. Our
approach provides a framework which permits the experts to design
the strategy map by applying a comprehensive and scientific method
together with their experience. Therefore this scheme is a more
reliable method in comparison with the previously established
methods.
Abstract: A new blind gray-level watermarking scheme is described. In the proposed method, the host image is first divided into 4*4 non-overlapping blocks. For each block, two first AC coefficients of its Hadamard transform are then estimated using DC coefficients of its neighbor blocks. A gray-level watermark is then added into estimated values. Since embedding watermark does not change the DC coefficients, watermark extracting could be done by estimating AC coefficients and comparing them with their actual values. Several experiments are made and results suggest the robustness of the proposed algorithm.
Abstract: In this study, a system of encryption based on chaotic
sequences is described. The system is used for encrypting digital
image data for the purpose of secure image transmission. An image
secure communication scheme based on Logistic map chaotic
sequences with a nonlinear function is proposed in this paper.
Encryption and decryption keys are obtained by one-dimensional
Logistic map that generates secret key for the input of the nonlinear
function. Receiver can recover the information using the received
signal and identical key sequences through the inverse system
technique. The results of computer simulations indicate that the
transmitted source image can be correctly and reliably recovered by
using proposed scheme even under the noisy channel. The
performance of the system will be discussed through evaluating the
quality of recovered image with and without channel noise.