Abstract: This paper examines the forced convection flow of
incompressible, electrically conducting viscous fluid past a sharp
wedge in the presence of heat generation or absorption with an
applied magnetic field. The system of partial differential equations
governing Falkner - Skan wedge flow and heat transfer is first
transformed into a system of ordinary differential equations using
similarity transformations which is later solved using an implicit
finite - difference scheme, along with quasilinearization technique.
Numerical computations are performed for air (Pr = 0.7) and
displayed graphically to illustrate the influence of pertinent physical
parameters on local skin friction and heat transfer coefficients and,
also on, velocity and temperature fields. It is observed that the
magnetic field increases both the coefficients of skin friction and heat
transfer. The effect of heat generation or absorption is found to be
very significant on heat transfer, but its effect on the skin friction is
negligible. Indeed, the occurrence of overshoot is noticed in the
temperature profiles during heat generation process, causing the
reversal in the direction of heat transfer.
Abstract: In this paper, a new adaptive Fourier decomposition
(AFD) based time-frequency speech analysis approach is proposed.
Given the fact that the fundamental frequency of speech signals often
undergo fluctuation, the classical short-time Fourier transform (STFT)
based spectrogram analysis suffers from the difficulty of window size
selection. AFD is a newly developed signal decomposition theory. It is
designed to deal with time-varying non-stationary signals. Its
outstanding characteristic is to provide instantaneous frequency for
each decomposed component, so the time-frequency analysis becomes
easier. Experiments are conducted based on the sample sentence in
TIMIT Acoustic-Phonetic Continuous Speech Corpus. The results
show that the AFD based time-frequency distribution outperforms the
STFT based one.
Abstract: Conventional approaches in the implementation of logic programming applications on embedded systems are solely of software nature. As a consequence, a compiler is needed that transforms the initial declarative logic program to its equivalent procedural one, to be programmed to the microprocessor. This approach increases the complexity of the final implementation and reduces the overall system's performance. On the contrary, presenting hardware implementations which are only capable of supporting logic programs prevents their use in applications where logic programs need to be intertwined with traditional procedural ones, for a specific application. We exploit HW/SW codesign methods to present a microprocessor, capable of supporting hybrid applications using both programming approaches. We take advantage of the close relationship between attribute grammar (AG) evaluation and knowledge engineering methods to present a programmable hardware parser that performs logic derivations and combine it with an extension of a conventional RISC microprocessor that performs the unification process to report the success or failure of those derivations. The extended RISC microprocessor is still capable of executing conventional procedural programs, thus hybrid applications can be implemented. The presented implementation is programmable, supports the execution of hybrid applications, increases the performance of logic derivations (experimental analysis yields an approximate 1000% increase in performance) and reduces the complexity of the final implemented code. The proposed hardware design is supported by a proposed extended C-language called C-AG.
Abstract: In this work, we successfully extended one-dimensional differential transform method (DTM), by presenting and proving some theorems, to solving nonlinear high-order multi-pantograph equations. This technique provides a sequence of functions which converges to the exact solution of the problem. Some examples are given to demonstrate the validity and applicability of the present method and a comparison is made with existing results.
Abstract: The kinematics of manipulators is a central problem in the automatic control of robot manipulators. Theoretical background for the analysis of the 5 Dof Lynx-6 educational Robot Arm kinematics is presented in this paper. The kinematics problem is defined as the transformation from the Cartesian space to the joint space and vice versa. The Denavit-Harbenterg (D-H) model of representation is used to model robot links and joints in this study. Both forward and inverse kinematics solutions for this educational manipulator are presented, An effective method is suggested to decrease multiple solutions in inverse kinematics. A visual software package, named MSG, is also developed for testing Motional Characteristics of the Lynx-6 Robot arm. The kinematics solutions of the software package were found to be identical with the robot arm-s physical motional behaviors.
Abstract: In this work, a radial basis function (RBF) neural network is developed for the identification of hyperbolic distributed parameter systems (DPSs). This empirical model is based only on process input-output data and used for the estimation of the controlled variables at specific locations, without the need of online solution of partial differential equations (PDEs). The nonlinear model that is obtained is suitably transformed to a nonlinear state space formulation that also takes into account the model mismatch. A stable robust control law is implemented for the attenuation of external disturbances. The proposed identification and control methodology is applied on a long duct, a common component of thermal systems, for a flow based control of temperature distribution. The closed loop performance is significantly improved in comparison to existing control methodologies.
Abstract: Wavelet transforms are multiresolution
decompositions that can be used to analyze signals and images.
Image compression is one of major applications of wavelet
transforms in image processing. It is considered as one of the most
powerful methods that provides a high compression ratio. However,
its implementation is very time-consuming. At the other hand,
parallel computing technologies are an efficient method for image
compression using wavelets. In this paper, we propose a parallel
wavelet compression algorithm based on quadtrees. We implement
the algorithm using MatlabMPI (a parallel, message passing version
of Matlab), and compute its isoefficiency function, and show that it is
scalable. Our experimental results confirm the efficiency of the
algorithm also.
Abstract: This paper presents a pulse doubling technique in a 12-pulse ac-dc converter which supplies direct torque controlled motor drives (DTCIMD-s) in order to have better power quality conditions at the point of common coupling. The proposed technique increases the number of rectification pulses without significant changes in the installations and yields in harmonic reduction in both ac and dc sides. The 12-pulse rectified output voltage is accomplished via two paralleled six-pulse ac-dc converters each of them consisting of three-phase diode bridge rectifier. An autotransformer is designed to supply the rectifiers. The design procedure of magnetics is in a way such that makes it suitable for retrofit applications where a six-pulse diode bridge rectifier is being utilized. Independent operation of paralleled diode-bridge rectifiers, i.e. dc-ripple re-injection methodology, requires a Zero Sequence Blocking Transformer (ZSBT). Finally, a tapped interphase reactor is connected at the output of ZSBT to double the pulse numbers of output voltage up to 24 pulses. The aforementioned structure improves power quality criteria at ac mains and makes them consistent with the IEEE-519 standard requirements for varying loads. Furthermore, near unity power factor is obtained for a wide range of DTCIMD operation. A comparison is made between 6- pulse, 12-pulse, and proposed converters from view point of power quality indices. Results show that input current total harmonic distortion (THD) is less than 5% for the proposed topology at various loads.
Abstract: In this study acoustic emission (AE) signals obtained during deformation and fracture of two types of ferrite-martensite dual phase steels (DPS) specimens have been analyzed in frequency domain. For this reason two low carbon steels with various amounts of carbon were chosen, and intercritically heat treated. In the introduced method, identifying the mechanisms of failure in the various phases of DPS is done. For this aim, AE monitoring has been used during tensile test of several DPS with various volume fraction of the martensite (VM) and attempted to relate the AE signals and failure mechanisms in these steels. Different signals, which referred to 2-3 micro-mechanisms of failure due to amount of carbon and also VM have been seen. By Fast Fourier Transformation (FFT) of signals in distinct locations, an excellent relationship between peak frequencies in these areas and micro-mechanisms of failure were seen. The results were verified by microscopic observations (SEM).
Abstract: Wikis are promoted as collaborative writing tools that
allow students to transform a text into a collective document by
information sharing and group reflection. However, despite the
promising collaborative capabilities of wikis, their pedagogical value
regarding collaborative writing is still questionable. Wiki alone
cannot make collaborative writing happen, and students do not
automatically become more active, participate, and collaborate with
others when they use wikis. To foster collaborative writing and active
involvement in wiki development there is a need for a systematic
approach to wikis. Themain goal of this paper is to propose and
evaluate a co-writing approach to the development of wikis, along
with the study of three wiki applications to report on pedagogical
implications of collaborative writing in higher education.
Abstract: Water pipe network is installed underground and once equipped, it is difficult to recognize the state of pipes when the leak or burst happens. Accordingly, post management is often delayed
after the fault occurs. Therefore, the systematic fault management system of water pipe network is required to prevent the accident and
minimize the loss. In this work, we develop online fault detection system of water pipe network using data of pipes such as flow rate
or pressure. The transient model describing water flow in pipelines
is presented and simulated using MATLAB. The fault situations such
as the leak or burst can be also simulated and flow rate or pressure data when the fault happens are collected. Faults are detected using
statistical methods of fast Fourier transform and discrete wavelet transform, and they are compared to find which method shows the
better fault detection performance.
Abstract: Cities denote instantaneously a challenge and an
opportunity for climate change policy. Cities are the place where
most energy services are needed because urbanization is closely
linked to high population densities and concentration of economic
activities and production (Urban energy demand). Consequently, it is
critical to explain about the role of cities within the world-s energy
systems and its correlation with the climate change issue. With more
than half of the world-s population already living in urban areas, and
that percentage expected to rise to 75 per cent by 2050, it is clear that
the path to sustainable development must pass through cities. Cities
expanding in size and population pose increased challenges to the
environment, of which energy is part as a natural resource, and to the
quality of life. Nowadays, most cities have already understood the
importance of sustainability, both at their local scale as in terms of
their contribution to sustainability at higher geographical scales. It
requires the perception of a city as a complex and dynamic
ecosystem, an open system, or cluster of systems, where the energy
as well as the other natural resources is transformed to satisfy the
needs of the different urban activities. In fact, buildings and
transportation generally represent most of cities direct energy
demand, i.e., between 60 per cent and 80 per cent of the overall
consumption. Buildings, both residential and services are usually
influenced by the local physical and social conditions. In terms of
transport, the energy demand is also strongly linked with the specific
characteristics of a city (urban mobility).The concept of a “smart
city" builds on statistics as seven key axes of a city-s success in
moving towards common platform (brain nerve)of sustainable urban
energy systems.
With the aforesaid knowledge, the authors have suggested a frame
work to role of cities, as energy actors for smart city management.
The authors have discusses the potential elements needed for energy
in smart cities and also identified potential energy actions and
relevant barriers. Furthermore, three levels of city smartness in cities
actions to overcome market /institutional failures with a local
approach are distinguished. The authors have made an attempt to
conceive and implement concepts of city smartness by adopting the
city or local government as nerve center through an integrated
planning approach. Finally, concluding with recommendations for
the organization of the Smart Sustainable Cities for positive changes
of urban India.
Abstract: Nowadays, obtaining traditional statistics and reports
is not adequate for the needs of organizational managers. The
managers need to analyze and to transform the raw data into
knowledge in the world filled with information. Therefore in this
regard various processes have been developed. In the meantime the
artificial intelligence-based processes are used and the new topics
such as business intelligence and knowledge discovery have
emerged. In the current paper it is sought to study the business
intelligence and its applications in the organizations.
Abstract: Truncated multiplier is a good candidate for digital
signal processing (DSP) applications including finite impulse
response (FIR) and discrete cosine transform (DCT). Through
truncated multiplier a significant reduction in Field Programmable
Gate Array (FPGA) resources can be achieved. This paper presents
for the first time a comparison of resource utilization of Spartan-3AN
and Virtex-5 implementation of standard and truncated multipliers
using Very High Speed Integrated Circuit Hardware Description
Language (VHDL). The Virtex-5 FPGA shows significant
improvement as compared to Spartan-3AN FPGA device. The
Virtex-5 FPGA device shows better performance with a percentage
ratio of number of occupied slices for standard to truncated
multipliers is increased from 40% to 73.86% as compared to Spartan-
3AN is decreased from 68.75% to 58.78%. Results show that the
anomaly in Spartan-3AN FPGA device average connection and
maximum pin delay have been efficiently reduced in Virtex-5 FPGA
device.
Abstract: This study reports the preparation of soft magnetic
ribbons of Fe-based amorphous alloys using the single-roller melt-spinning technique. Ribbon width varied from 142 mm to 213
mm and, with a thickness of approximately 22 μm ± 2 μm. The microstructure and magnetic properties of the ribbons were
characterized by differential scanning calorimeter (DSC), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and electrical resistivity measurements (ERM). The amorphous material
properties dependence of the cooling rate and nozzle pressure have uneven surface in ribbon thicknesses are investigated. Magnetic
measurement results indicate that some region of the ribbon exhibits good magnetic properties, higher saturation induction and lower coercivity. However, due to the uneven surface of 213 mm wide
ribbon, the magnetic responses are not uniformly distributed. To
understand the transformer magnetic performances, this study analyzes the measurements of a three-phase 2 MVA amorphous-cored transformer. Experimental results confirm that the transformer with a
ribbon width of 142 mm has better magnetic properties in terms of lower core loss, exciting power, and audible noise.
Abstract: Fractional Fourier Transform, which is a
generalization of the classical Fourier Transform, is a powerful tool
for the analysis of transient signals. The discrete Fractional Fourier
Transform Hamiltonians have been proposed in the past with varying
degrees of correlation between their eigenvectors and Hermite
Gaussian functions. In this paper, we propose a new Hamiltonian for
the discrete Fractional Fourier Transform and show that the
eigenvectors of the proposed matrix has a higher degree of
correlation with the Hermite Gaussian functions. Also, the proposed
matrix is shown to give better Fractional Fourier responses with
various transform orders for different signals.
Abstract: A method is presented for obtaining the error probability for block codes. The method is based on the eigenvalueeigenvector properties of the code correlation matrix. It is found that under a unary transformation and for an additive white Gaussian noise environment, the performance evaluation of a block code becomes a one-dimensional problem in which only one eigenvalue and its corresponding eigenvector are needed in the computation. The obtained error rate results show remarkable agreement between simulations and analysis.
Abstract: A dual-reciprocity boundary element method is presented
for the numerical solution of a class of axisymmetric elastodynamic
problems. The domain integrals that arise in the integrodifferential
formulation are converted to line integrals by using the
dual-reciprocity method together suitably constructed interpolating
functions. The second order time derivatives of the displacement
in the governing partial differential equations are suppressed by
using Laplace transformation. In the Laplace transform domain, the
problem under consideration is eventually reduced to solving a system
of linear algebraic equations. Once the linear algebraic equations are
solved, the displacement and stress fields in the physical domain can
be recovered by using a numerical technique for inverting Laplace
transforms.
Abstract: In this paper, we study on color transformation
method on website images for the color blind. The most common
category of color blindness is red-green color blindness which is
viewed as beige color. By transforming the colors of the images, the
color blind can improve their color visibility. They can have a better
view when browsing through the websites. To transform colors on
the website images, we study on two algorithms which are the
conversion techniques from RGB color space to HSV color space and
self-organizing color transformation. The comparative study focuses
on criteria based on the ease of use, quality, accuracy and efficiency.
The outcome of the study leads to enhancement of website images to
meet the color blinds- vision requirements in perceiving image
detailed.
Abstract: Safety Critical hard Real-Time Systems are ever
present in the avionics industry. The Model Driven Architecture
(MDA) offers different levels of model abstraction and generation.
This paper discusses our concerns relating to model development and
generation when using the MDA approach in the avionics industry.
These concerns are based on our experience when looking into
adopting the MDA as part of avionics systems development. We
place emphasis on transformations between model types and discuss
possible benefits of adopting an MDA approach as part of the
software development life cycle.