Abstract: Distant-talking voice-based HCI system suffers from
performance degradation due to mismatch between the acoustic
speech (runtime) and the acoustic model (training). Mismatch is
caused by the change in the power of the speech signal as observed at
the microphones. This change is greatly influenced by the change in
distance, affecting speech dynamics inside the room before reaching
the microphones. Moreover, as the speech signal is reflected, its
acoustical characteristic is also altered by the room properties. In
general, power mismatch due to distance is a complex problem. This
paper presents a novel approach in dealing with distance-induced
mismatch by intelligently sensing instantaneous voice power variation
and compensating model parameters. First, the distant-talking speech
signal is processed through microphone array processing, and the
corresponding distance information is extracted. Distance-sensitive
Gaussian Mixture Models (GMMs), pre-trained to capture both
speech power and room property are used to predict the optimal
distance of the speech source. Consequently, pre-computed statistic
priors corresponding to the optimal distance is selected to correct
the statistics of the generic model which was frozen during training.
Thus, model combinatorics are post-conditioned to match the power
of instantaneous speech acoustics at runtime. This results to an
improved likelihood in predicting the correct speech command at
farther distances. We experiment using real data recorded inside two
rooms. Experimental evaluation shows voice recognition performance
using our method is more robust to the change in distance compared
to the conventional approach. In our experiment, under the most
acoustically challenging environment (i.e., Room 2: 2.5 meters), our
method achieved 24.2% improvement in recognition performance
against the best-performing conventional method.
Abstract: Transesterified vegetable oils (biodiesel) are promising alternative fuel for diesel engines. Used vegetable oils are disposed from restaurants in large quantities. But higher viscosity restricts their direct use in diesel engines. In this study, used cooking oil was dehydrated and then transesterified using an alkaline catalyst. The combustion, performance and emission characteristics of Used Cooking oil Methyl Ester (UCME) and its blends with diesel oil are analysed in a direct injection C.I. engine. The fuel properties and the combustion characteristics of UCME are found to be similar to those of diesel. A minor decrease in thermal efficiency with significant improvement in reduction of particulates, carbon monoxide and unburnt hydrocarbons is observed compared to diesel. The use of transesterified used cooking oil and its blends as fuel for diesel engines will reduce dependence on fossil fuels and also decrease considerably the environmental pollution.
Abstract: Multi-dimensional principal component analysis
(PCA) is the extension of the PCA, which is used widely as the
dimensionality reduction technique in multivariate data analysis, to
handle multi-dimensional data. To calculate the PCA the singular
value decomposition (SVD) is commonly employed by the reason of
its numerical stability. The multi-dimensional PCA can be calculated
by using the higher-order SVD (HOSVD), which is proposed by
Lathauwer et al., similarly with the case of ordinary PCA. In this
paper, we apply the multi-dimensional PCA to the multi-dimensional
medical data including the functional independence measure (FIM)
score, and describe the results of experimental analysis.
Abstract: In the last two decades radiofrequency ablation (RFA)
has been considered a promising medical procedure for the treatment
of primary and secondary malignancies. However, the needle-based
electrodes so far developed for this kind of treatment are not suitable
for the thermal ablation of tumors located in hollow organs like
esophagus, colon or bile duct. In this work a tubular electrode
solution is presented. Numerical and experimental analyses were
performed to characterize the volume of the lesion induced. Results
show that this kind of electrode is a feasible solution and numerical
simulation might provide a tool for planning RFA procedure with
some accuracy.
Abstract: Coronary artery bypass grafts (CABG) are widely
studied with respect to hemodynamic conditions which play
important role in presence of a restenosis. However, papers which
concern with constitutive modeling of CABG are lacking in the
literature. The purpose of this study is to find a constitutive model for
CABG tissue. A sample of the CABG obtained within an autopsy
underwent an inflation–extension test. Displacements were
recoredered by CCD cameras and subsequently evaluated by digital
image correlation. Pressure – radius and axial force – elongation
data were used to fit material model. The tissue was modeled as onelayered
composite reinforced by two families of helical fibers. The
material is assumed to be locally orthotropic, nonlinear,
incompressible and hyperelastic. Material parameters are estimated
for two strain energy functions (SEF). The first is classical
exponential. The second SEF is logarithmic which allows
interpretation by means of limiting (finite) strain extensibility.
Presented material parameters are estimated by optimization based
on radial and axial equilibrium equation in a thick-walled tube. Both
material models fit experimental data successfully. The exponential
model fits significantly better relationship between axial force and
axial strain than logarithmic one.
Abstract: This work describes the aerodynamic characteristic for
aircraft wing model with and without bird feather like winglet. The
aerofoil used to construct the whole structure is NACA 653-218
Rectangular wing and this aerofoil has been used to compare the
result with previous research using winglet. The model of the
rectangular wing with bird feather like winglet has been fabricated
using polystyrene before design using CATIA P3 V5R13 software
and finally fabricated in wood. The experimental analysis for the
aerodynamic characteristic for rectangular wing without winglet,
wing with horizontal winglet and wing with 60 degree inclination
winglet for Reynolds number 1.66×105, 2.08×105 and 2.50×105 have
been carried out in open loop low speed wind tunnel at the
Aerodynamics laboratory in Universiti Putra Malaysia. The
experimental result shows 25-30 % reduction in drag coefficient and
10-20 % increase in lift coefficient by using bird feather like winglet
for angle of attack of 8 degree.
Abstract: Modeling transfer phenomena in several chemical
engineering operations leads to the resolution of partial differential
equations systems. According to the complexity of the operations
mechanisms, the equations present a nonlinear form and analytical
solution became difficult, we have then to use numerical methods
which are based on approximations in order to transform a
differential system to an algebraic one.Finite element method is one
of numerical methods which can be used to obtain an accurate
solution in many complex cases of chemical engineering.The packed
columns find a large application like contactor for liquid-liquid
systems such solvent extraction. In the literature, the modeling of this
type of equipment received less attention in comparison with the
plate columns.A mathematical bidimensionnal model with radial and
axial dispersion, simulating packed tower extraction behavior was
developed and a partial differential equation was solved using the
finite element method by adopting the Galerkine model. We
developed a Mathcad program, which can be used for a similar
equations and concentration profiles are obtained along the column.
The influence of radial dispersion was prooved and it can-t be
neglected, the results were compared with experimental concentration
at the top of the column in the extraction system:
acetone/toluene/water.
Abstract: In the recent works related with mixture discriminant
analysis (MDA), expectation and maximization (EM) algorithm is
used to estimate parameters of Gaussian mixtures. But, initial values
of EM algorithm affect the final parameters- estimates. Also, when
EM algorithm is applied two times, for the same data set, it can be
give different results for the estimate of parameters and this affect the
classification accuracy of MDA. Forthcoming this problem, we use
Self Organizing Mixture Network (SOMN) algorithm to estimate
parameters of Gaussians mixtures in MDA that SOMN is more robust
when random the initial values of the parameters are used [5]. We
show effectiveness of this method on popular simulated waveform
datasets and real glass data set.
Abstract: Clustering algorithms help to understand the hidden
information present in datasets. A dataset may contain intrinsic and
nested clusters, the detection of which is of utmost importance. This
paper presents a Distributed Grid-based Density Clustering algorithm
capable of identifying arbitrary shaped embedded clusters as well as
multi-density clusters over large spatial datasets. For handling
massive datasets, we implemented our method using a 'sharednothing'
architecture where multiple computers are interconnected
over a network. Experimental results are reported to establish the
superiority of the technique in terms of scale-up, speedup as well as
cluster quality.
Abstract: In the present work, behavior of inoxydable steel as
reinforcement bar in composite concrete is being investigated. The
bar-concrete adherence in reinforced concrete (RC) beam is studied
and focus is made on the tension stiffening parameter. This study
highlighted an approach to observe this interaction behavior in
bending test instead of direct tension as per reported in many
references. The approach resembles actual loading condition of the
structural RC beam. The tension stiffening properties are then
applied to numerical finite element analysis (FEA) to verify their
correlation with laboratory results. Comparison with laboratory
shows a good correlation between the two. The experimental settings
is able to determine tension stiffening parameters in RC beam and
the modeling strategies made in ABAQUS can closely represent the
actual condition. Tension stiffening model used can represent the
interaction properties between inoxydable steel and concrete.
Abstract: As a part of the development of a numerical method of
close capture exhausts systems for machining devices, a test rig
recreating a situation similar to a grinding operation, but in a
perfectly controlled environment, is used. The properties of the
obtained spray of solid particles are initially characterized using
particle tracking velocimetry (PTV), in order to obtain input and
validation parameters for numerical simulations. The dispersion of a
tracer gas (SF6) emitted simultaneously with the particle jet is then
studied experimentally, as the dispersion of such a gas is
representative of that of finer particles, whose aerodynamic response
time is negligible. Finally, complete modeling of the test rig is
achieved to allow comparison with experimental results and thus to
progress towards validation of the models used to describe a twophase
flow generated by machining operation.
Abstract: This paper reports on the results of experimental
investigations of flash evaporation from superheated jet issues
vertically upward from a round straight nozzle of 81.3 mm diameter.
For the investigated range of jet superheat degree and velocity, it was
shown that flash evaporation enhances with initial temperature
increase. Due to the increase of jet inertia and subsequently the delay
of jet shattering, increase of jet velocity was found to result in
increase of evaporation "delay period". An empirical equation
predicts the jet evaporation completion height was developed, this
equation is thought to be useful in designing the flash evaporation
chamber. In attempts for enhancement of flash evaporation, use of
steel wire mesh located at short distance downstream was found
effective with no consequent pressure drop.
Abstract: The main aim of this work is to develop a model of hydrogen sulfide (H2S) separation from natural gas by using membrane separation technology. The model is developed by incorporating three diffusion mechanisms which are Knudsen, viscous and surface diffusion towards membrane selectivity and permeability. The findings from the simulation result shows that the permeability of the gas is dependent toward the pore size of the membrane, operating pressure, operating temperature as well as feed composition. The permeability of methane has the highest value for Poly (1-trimethylsilyl-1-propyne ) PTMSP membrane at pore size of 0.1nm and decreasing toward a minimum peak at pore range 1 to 1.5 nm as pore size increased before it increase again for pore size is greater than 1.5 nm. On the other hand, the permeability of hydrogen sulfide is found to increase almost proportionally with the increase of membrane pore size. Generally, the increase of pressure will increase the permeability of gas since more driving force is provided to the system while increasing of temperature would decrease the permeability due to the surface diffusion drop off effect. A corroboration of the simulation result also showed a good agreement with the experimental data.
Abstract: This paper presents the experimental results of
leakage current waveforms which appears on porcelain insulator
surface due to existence of artificial pollutants. The tests have been
done using the chemical compounds of NaCl, Na2SiO3, H2SO4, CaO,
Na2SO4, KCl, Al2SO4, MgSO4, FeCl3, and TiO2. The insulator
surface was coated with those compounds and dried. Then, it was
tested in the chamber where the high voltage was applied. Using
correspondence analysis, the result indicated that the fundamental
harmonic of leakage current was very close to the applied voltage
and third harmonic leakage current was close to the yielded leakage
current amplitude. The first harmonic power was correlated to first
harmonic amplitude of leakage current, and third harmonic power
was close to third harmonic one. The chemical compounds of H2SO4
and Na2SiO3 affected to the power factor of around 70%. Both are the
most conductive, due to the power factor drastically increase among
the chemical compounds.
Abstract: Experimental investigation has been carried out
towards understanding the complex fluid dynamics involved in the
interaction of vortical structures with zero pressure gradient boundary
layer. A laminar boundary layer is produced on the flat plate placed
in the water flume and the synthetic jet actuator is deployed on top of
the plate at a definite distance from the leading edge. The synthetic
jet actuator has been designed in such a way that the to and fro
motion of the diaphragm is maneuvered at will by varying the
operating parameters to produce the typical streamwise vortical
structures namely hairpin and tilted vortices. PIV measurements are
made on the streamwise plane normal to the plate to evaluate their
interaction with the near wall fluid.
Abstract: Three-dimensional reconstruction of small objects has
been one of the most challenging problems over the last decade.
Computer graphics researchers and photography professionals have
been working on improving 3D reconstruction algorithms to fit the
high demands of various real life applications. Medical sciences,
animation industry, virtual reality, pattern recognition, tourism
industry, and reverse engineering are common fields where 3D
reconstruction of objects plays a vital role. Both lack of accuracy and
high computational cost are the major challenges facing successful
3D reconstruction. Fringe projection has emerged as a promising 3D
reconstruction direction that combines low computational cost to both
high precision and high resolution. It employs digital projection,
structured light systems and phase analysis on fringed pictures.
Research studies have shown that the system has acceptable
performance, and moreover it is insensitive to ambient light.
This paper presents an overview of fringe projection approaches. It
also presents an experimental study and implementation of a simple
fringe projection system. We tested our system using two objects
with different materials and levels of details. Experimental results
have shown that, while our system is simple, it produces acceptable
results.
Abstract: This paper presents a model for the evaluation of
energy performance and aerodynamic forces acting on a small
straight-bladed Darrieus-type vertical axis wind turbine depending on
blade geometrical section. It consists of an analytical code coupled to
a solid modeling software, capable of generating the desired blade
geometry based on the desired blade design geometric parameters.
Such module is then linked to a finite volume commercial CFD code
for the calculation of rotor performance by integration of the
aerodynamic forces along the perimeter of each blade for a full period
of revolution.After describing and validating the computational
model with experimental data, the results of numerical simulations
are proposed on the bases of two candidate airfoil sections, that is a
classical symmetrical NACA 0021 blade profile and the recently
developed DU 06-W-200 non-symmetric and laminar blade
profile.Through a full CFD campaign of analysis, the effects of blade
geometrical section on angle of attack are first investigated and then
the overall rotor torque and power are analyzed as a function of blade
azimuthal position, achieving a numerical quantification of the
influence of airfoil geometry on overall rotor performance.
Abstract: Understanding of how and where NOx formation
occurs in industrial burner is very important for efficient and clean
operation of utility burners. Also the importance of this problem is
mainly due to its relation to the pollutants produced by more burners
used widely of gas turbine in thermal power plants and glass and steel
industry.
In this article, a numerical model of an industrial burner operating
in MILD combustion is validated with experimental data.. Then
influence of air flow rate and air temperature on combustor
temperature profiles and NOX product are investigated. In order to
modification this study reports on the effects of fuel and air dilution
(with inert gases H2O, CO2, N2), and also influence of lean-premixed
of fuel, on the temperature profiles and NOX emission.
Conservation equations of mass, momentum and energy, and
transport equations of species concentrations, turbulence, combustion
and radiation modeling in addition to NO modeling equations were
solved together to present temperature and NO distribution inside the
burner.
The results shows that dilution, cause to a reduction in value of
temperature and NOX emission, and suppresses any flame
propagation inside the furnace and made the flame inside the furnace
invisible. Dilution with H2O rather than N2 and CO2 decreases further
the value of the NOX. Also with raise of lean-premix level, local
temperature of burner and the value of NOX product are decreases
because of premixing prevents local “hot spots" within the combustor
volume that can lead to significant NOx formation. Also leanpremixing
of fuel with air cause to amount of air in reaction zone is
reach more than amount that supplied as is actually needed to burn
the fuel and this act lead to limiting NOx formation
Abstract: Column leach test has been performed to examine the
behavior of leaching of sodium, calcium and potassium in landfills.
In the column leach apparatus, two different layers of contaminated
and uncontaminated soils of different height ratios (ratio of depth of
contaminated soil to the depth of uncontaminated soil) are taken.
Water is poured from an overhead tank at a particular flowrate to the
inlet of the soil column for a certain ponding depth over the
contaminated soil. Subsequent infiltration causes leaching and the
leachates are collected from the bottom of the column. The
concentrations of Na, Ca and K in the leachate are measured using
flame photometry. The experiments are further extended by changing
the rates of flow from the overhead tank to the inlet of the column in
achieving the same ponding depth. The experiments are performed
for different scenarios in which the height ratios are altered and the
variations of concentrations of Na, Ca, and K are observed. The study
brings an estimation of leaching in landfill sites for different heights
and precipitation intensity where a ponding depth is maintained over
the landfill. It has been observed that the leaching behavior of Na,
Ca, and K are not similar. Calcium exhibits highest amount of
leaching compared to Sodium and Potassium under similar
experimental conditions.
Abstract: In the present study, Convective heat transfer
coefficient and pressure drop of Al2O3/water nanofluid in laminar
flow regime under constant heat flux conditions inside a circular tube
were experimentally investigated. Al2O3/water nanofluid with 0.5%
and 1% volume concentrations with 15 nm diameter nanoparticles
were used as working fluid. The effect of different volume
concentrations on convective heat transfer coefficient and friction
factor was studied. The results emphasize that increasing of particle
volume concentration leads to enhance convective heat transfer
coefficient. Measurements show the average heat transfer coefficient
enhanced about 11-20% with 0.5% volume concentration and
increased about 16-27% with 1% volume concentration compared to
distilled water. In addition, the convective heat transfer coefficient of
nanofluid enhances with increase in heat flux. From the results, the
average ratio of (fnf/fbf) was about 1.10 for 0.5% volume
concentration. Therefore, there is no significant increase in friction
factor for nanofluids.