Abstract: In this paper the Differential Quadrature Method (DQM) is employed to study the coupled lateral-torsional free vibration behavior of the laminated composite beams. In such structures due to the fiber orientations in various layers, the lateral displacement leads to a twisting moment. The coupling of lateral and torsional vibrations is modeled by the bending-twisting material coupling rigidity. In the present study, in addition to the material coupling, the effects of shear deformation and rotary inertia are taken into account in the definition of the potential and kinetic energies of the beam. The governing differential equations of motion which form a system of three coupled PDEs are solved numerically using DQ procedure under different boundary conditions consist of the combinations of simply, clamped, free and other end conditions. The resulting natural frequencies and mode shapes for cantilever beam are compared with similar results in the literature and good agreement is achieved.
Abstract: A new method identifies coupled fluid-structure system with a reduced set of state variables is presented. Assuming that the structural model is known a priori either from an analysis or a test and using linear transformations between structural and aeroelastic states, it is possible to deduce aerodynamic information from sampled time histories of the aeroelastic system. More specifically given a finite set of structural modes the method extracts generalized aerodynamic force matrix corresponding to these mode shapes. Once the aerodynamic forces are known, an aeroelastic reduced-order model can be constructed in discrete-time, state-space format by coupling the structural model and the aerodynamic system. The resulting reduced-order model is suitable for constant Mach, varying density analysis.
Abstract: Modeling and vibration of a flexible link manipulator
with tow flexible links and rigid joints are investigated which can
include an arbitrary number of flexible links. Hamilton principle and
finite element approach is proposed to model the dynamics of
flexible manipulators. The links are assumed to be deflection due to
bending. The association between elastic displacements of links is
investigated, took into account the coupling effects of elastic motion
and rigid motion. Flexible links are treated as Euler-Bernoulli beams
and the shear deformation is thus abandoned. The dynamic behavior
due to flexibility of links is well demonstrated through numerical
simulation. The rigid-body motion and elastic deformations are
separated by linearizing the equations of motion around the rigid
body reference path. Simulation results are shown on for both
position and force trajectory tracking tasks in the presence of varying
parameters and unknown dynamics remarkably well. The proposed
method can be used in both dynamic simulation and controller
design.
Abstract: In this work we present the modelling of the induction
machine, taking into consideration the stator defects of the induction
machine. It is based on the theory of electromagnetic coupling of
electrical circuits. In fact, for the modelling of stationary defects such
as short circuit between turns in the same phase, we introduce only
in the matrix the coefficients of resistance and inductance of stator
and in the mutual inductance stator-rotor. These coefficients take
account the number of turns in short-circuit deducted from the total
number of turns in the same phase; in this way we obtain the number
of useful turns. In addition, all these faults involved, will be used for
the creation of the database that will be used to develop an automated
system failures of the induction machine.
Abstract: The iron loss is a source of detuning in vector controlled
induction motor drives if the classical rotor vector controller is used for
decoupling. In fact, the field orientation will not be satisfied and the
output torque will not truck the reference torque mostly used by Loss
Model Controllers (LMCs). In addition, this component of loss, among
others, may be excessive if the vector controlled induction motor is
driving light loads. In this paper, the series iron loss model is used to
develop a vector controller immune to iron loss effect and then an LMC
to minimize the total power loss using the torque generated by the speed
controller.
Abstract: Droplet size distributions in the cold spray of a fuel
are important in observed combustion behavior. Specification of
droplet size and velocity distributions in the immediate downstream
of injectors is also essential as boundary conditions for advanced
computational fluid dynamics (CFD) and two-phase spray transport
calculations. This paper describes the development of a new model to
be incorporated into maximum entropy principle (MEP) formalism
for prediction of droplet size distribution in droplet formation region.
The MEP approach can predict the most likely droplet size and
velocity distributions under a set of constraints expressing the
available information related to the distribution.
In this article, by considering the mechanisms of turbulence
generation inside the nozzle and wave growth on jet surface, it is
attempted to provide a logical framework coupling the flow inside the
nozzle to the resulting atomization process. The purpose of this paper
is to describe the formulation of this new model and to incorporate it
into the maximum entropy principle (MEP) by coupling sub-models
together using source terms of momentum and energy. Comparison
between the model prediction and experimental data for a gas turbine
swirling nozzle and an annular spray indicate good agreement
between model and experiment.
Abstract: Wireless channels are characterized by more serious
bursty and location-dependent errors. Many packet scheduling
algorithms have been proposed for wireless networks to guarantee
fairness and delay bounds. However, most existing schemes do not
consider the difference of traffic natures among packet flows. This
will cause the delay-weight coupling problem. In particular, serious
queuing delays may be incurred for real-time flows. In this paper, it
is proposed a scheduling algorithm that takes traffic types of flows
into consideration when scheduling packets and also it is provided
scheduling flexibility by trading off video quality to meet the
playback deadline.
Abstract: A novel direction-of-arrival (DOA) estimation technique, which uses a conventional multiple signal classification (MUSIC) algorithm with periodic signals, is applied to a single RF-port parasitic array antenna for direction finding. Simulation results show that the proposed method gives high resolution (1 degree) DOA estimation in an uncorrelated signal environment. The novelty lies in that the MUSIC algorithm is applied to a simplified antenna configuration. Only one RF port and one analogue-to-digital converter (ADC) are used in this antenna, which features low DC power consumption, low cost, and ease of fabrication. Modifications to the conventional MUSIC algorithm do not bring much additional complexity. The proposed technique is also free from the negative influence by the mutual coupling between elements. Therefore, the technique has great potential to be implemented into the existing wireless mobile communications systems, especially at the power consumption limited mobile terminals, to provide additional position location (PL) services.
Abstract: This article is an extension and a practical application
approach of Wheeler-s NEBIC theory (Net Enabled Business
Innovation Cycle). NEBIC theory is a new approach in IS research
and can be used for dynamic environment related to new technology.
Firms can follow the market changes rapidly with support of the IT
resources. Flexible firms adapt their market strategies, and respond
more quickly to customers changing behaviors. When every leading
firm in an industry has access to the same IT resources, the way that
these IT resources are managed will determine the competitive
advantages or disadvantages of firm. From Dynamic Capabilities
Perspective and from newly introduced NEBIC theory by Wheeler,
we know that only IT resources cannot deliver customer value but
good configuration of those resources can guarantee customer value
by choosing the right emerging technology, grasping the right
economic opportunities through business innovation and growth. We
found evidences in literature that SOA (Service Oriented
Architecture) is a promising emerging technology which can deliver
the desired economic opportunity through modularity, flexibility and
loose-coupling. SOA can also help firms to connect in network which
can open a new window of opportunity to collaborate in innovation
and right kind of outsourcing. There are many articles and research
reports indicates that failure rate in outsourcing is very high but at the
same time research indicates that successful outsourcing projects
adds tangible and intangible benefits to the service consumer.
Business executives and policy makers in the west should not afraid
of outsourcing but they should choose the right strategy through the
use of emerging technology to significantly reduce the failure rate in
outsourcing.
Abstract: In this paper we introduce a novel method for
the characterization of synchronziation and coupling effects
in multivariate time series that can be used for the analysis
of EEG or ECoG signals recorded during epileptic seizures.
The method allows to visualize the spatio-temporal evolution
of synchronization and coupling effects that are characteristic
for epileptic seizures. Similar to other methods proposed for
this purpose our method is based on a regression analysis.
However, a more general definition of the regression together
with an effective channel selection procedure allows to use the
method even for time series that are highly correlated, which
is commonly the case in EEG/ECoG recordings with large
numbers of electrodes. The method was experimentally tested
on ECoG recordings of epileptic seizures from patients with
temporal lobe epilepsies. A comparision with the results from
a independent visual inspection by clinical experts showed
an excellent agreement with the patterns obtained with the
proposed method.
Abstract: In today-s hip hop world where everyone is running
short of time and works hap hazardly,the similar scene is common on
the roads while in traffic.To do away with the fatal consequences of
such speedy traffics on rushy lanes, a software to analyse and keep
account of the traffic and subsequent conjestion is being used in the
developed countries. This software has being implemented and used
with the help of a suppprt tool called Critical Analysis Reporting
Environment.There has been two existing versions of this tool.The
current research paper involves examining the issues and probles
while using these two practically. Further a hybrid architecture is
proposed for the same that retains the quality and performance of
both and is better in terms of coupling of components , maintainence
and many other features.
Abstract: The cost of developing the software from scratch can
be saved by identifying and extracting the reusable components from
already developed and existing software systems or legacy systems
[6]. But the issue of how to identify reusable components from
existing systems has remained relatively unexplored. We have used
metric based approach for characterizing a software module. In this
present work, the metrics McCabe-s Cyclometric Complexity
Measure for Complexity measurement, Regularity Metric, Halstead
Software Science Indicator for Volume indication, Reuse Frequency
metric and Coupling Metric values of the software component are
used as input attributes to the different types of Neural Network
system and reusability of the software component is calculated. The
results are recorded in terms of Accuracy, Mean Absolute Error
(MAE) and Root Mean Squared Error (RMSE).
Abstract: The resistive-inductive-capacitive behavior of long
interconnects which are driven by CMOS gates are presented in this
paper. The analysis is based on the ¤Ç-model of a RLC load and is
developed for submicron devices. Accurate and analytical
expressions for the output load voltage, the propagation delay and the
short circuit power dissipation have been proposed after solving a
system of differential equations which accurately describe the
behavior of the circuit. The effect of coupling capacitance between
input and output and the short circuit current on these performance
parameters are also incorporated in the proposed model. The
estimated proposed delay and short circuit power dissipation are in
very good agreement with the SPICE simulation with average
relative error less than 6%.
Abstract: In this work we numerically examine structures which
could confine light in nanometer areas. A system consisting of two silicon disks with in plane separation of a few tens of nanometers has
been studied first. The normalized unitless effective mode volume, Veff, has been calculated for the two lowest whispering gallery mode resonances. The effective mode volume is reduced significantly as the gap between the disks decreases. In addition, the effect of the substrate is also studied. In that case, Veff of approximately the same
value as the non-substrate case for a similar two disk system can be
obtained by using disks almost twice as thick. We also numerically examine a structure consisting of a circular slot waveguide which is formed into a silicon disk resonator. We show that the proposed structure could have high Q resonances thus raising the belief that it
is a very promising candidate for optical interconnects applications.
The study includes several numerical calculations for all the geometric parameters of the structure. It also includes numerical simulations of the coupling between a waveguide and the proposed
disk resonator leading to a very promising conclusion about its applicability.
Abstract: Nowadays, Gene Ontology has been used widely by many researchers for biological data mining and information retrieval, integration of biological databases, finding genes, and incorporating knowledge in the Gene Ontology for gene clustering. However, the increase in size of the Gene Ontology has caused problems in maintaining and processing them. One way to obtain their accessibility is by clustering them into fragmented groups. Clustering the Gene Ontology is a difficult combinatorial problem and can be modeled as a graph partitioning problem. Additionally, deciding the number k of clusters to use is not easily perceived and is a hard algorithmic problem. Therefore, an approach for solving the automatic clustering of the Gene Ontology is proposed by incorporating cohesion-and-coupling metric into a hybrid algorithm consisting of a genetic algorithm and a split-and-merge algorithm. Experimental results and an example of modularized Gene Ontology in RDF/XML format are given to illustrate the effectiveness of the algorithm.
Abstract: In this paper, the dynamics of a system of two van der Pol oscillators with delayed position and velocity is studied. We provide an approximate solution for this system using parameterexpansion method. Also, we obtain approximate values for frequencies of the system. The parameter-expansion method is more efficient than the perturbation method for this system because the method is independent of perturbation parameter assumption.
Abstract: It is known that the heart interacts with and adapts to
its venous and arterial loading conditions. Various experimental
studies and modeling approaches have been developed to investigate
the underlying mechanisms. This paper presents a model of the left
ventricle derived based on nonlinear stress-length myocardial
characteristics integrated over truncated ellipsoidal geometry, and
second-order dynamic mechanism for the excitation-contraction
coupling system. The results of the model presented here describe the
effects of the viscoelastic damping element of the electromechanical
coupling system on the hemodynamic response. Different heart rates
are considered to study the pacing effects on the performance of the
left-ventricle against constant preload and afterload conditions under
various damping conditions. The results indicate that the pacing
process of the left ventricle has to take into account, among other
things, the viscoelastic damping conditions of the myofilament
excitation-contraction process.
Abstract: The malfunction of thermal protection system (TPS) caused by aerodynamic heating is a latent trouble to aircraft structure safety. Accurately predicting the structure temperature field is quite important for the TPS design of hypersonic vehicle. Since Thornton’s work in 1988, the coupled method of aerodynamic heating and heat transfer has developed rapidly. However, little attention has been paid to the influence of structural deformation on aerodynamic heating and structural temperature field. In the flight, especially the long-endurance flight, the structural deformation, caused by the aerodynamic heating and temperature rise, has a direct impact on the aerodynamic heating and structural temperature field. Thus, the coupled interaction cannot be neglected. In this paper, based on the method of static aero-thermo-elasticity, considering the influence of aero-thermo-elasticity deformation, the aerodynamic heating and heat transfer coupled results of hypersonic vehicle wing model were calculated. The results show that, for the low-curvature region, such as fuselage or center-section wing, structure deformation has little effect on temperature field. However, for the stagnation region with high curvature, the coupled effect is not negligible. Thus, it is quite important for the structure temperature prediction to take into account the effect of elastic deformation. This work has laid a solid foundation for improving the prediction accuracy of the temperature distribution of aircraft structures and the evaluation capacity of structural performance.
Abstract: This paper presents a dynamic model for mechanical
loads of an electric drive, including angular misalignment and
including load unbalance. The misalignment model represents the
effects of the universal joint between the motor and the mechanical
load. Simulation results are presented for an induction motor driving
a mechanical load with angular misalignment for both flexible and
rigid coupling. The models presented are very useful in the study of
mechanical fault detection in induction motors, using mechanical and
electrical signals already available in a drive system, such as speed,
torque and stator currents.
Abstract: This paper adopted the hybrid differential transform approach for studying heat transfer problems in a gold/chromium thin film with an ultra-short-pulsed laser beam projecting on the gold side. The physical system, formulated based on the hyperbolic two-step heat transfer model, covers three characteristics: (i) coupling effects between the electron/lattice systems, (ii) thermal wave propagation in metals, and (iii) radiation effects along the interface. The differential transform method is used to transfer the governing equations in the time domain into the spectrum equations, which is further discretized in the space domain by the finite difference method. The results, obtained through a recursive process, show that the electron temperature in the gold film can rise up to several thousand degrees before its electron/lattice systems reach equilibrium at only several hundred degrees. The electron and lattice temperatures in the chromium film are much lower than those in the gold film.