Abstract: In this study, we propose a novel technique for acoustic
echo suppression (AES) during speech recognition under barge-in
conditions. Conventional AES methods based on spectral subtraction
apply fixed weights to the estimated echo path transfer function
(EPTF) at the current signal segment and to the EPTF estimated until
the previous time interval. However, the effects of echo path changes
should be considered for eliminating the undesired echoes. We
describe a new approach that adaptively updates weight parameters in
response to abrupt changes in the acoustic environment due to
background noises or double-talk. Furthermore, we devised a voice
activity detector and an initial time-delay estimator for barge-in speech
recognition in communication networks. The initial time delay is
estimated using log-spectral distance measure, as well as
cross-correlation coefficients. The experimental results show that the
developed techniques can be successfully applied in barge-in speech
recognition systems.
Abstract: The study is devoted to define the optimal conditions
for the nitriding of pure iron at atmospheric pressure by using NH3-
Ar-C3H8 gas mixtures. After studying the mechanisms of phase
formation and mass transfer at the gas-solid interface, a mathematical
model is developed in order to predict the nitrogen transfer rate in the
solid, the ε-carbonitride layer growth rate and the nitrogen and
carbon concentration profiles. In order to validate the model and to
show its possibilities, it is compared with thermogravimetric
experiments, analyses and metallurgical observations (X-ray
diffraction, optical microscopy and electron microprobe analysis).
Results obtained allow us to demonstrate the sound correlation
between the experimental results and the theoretical predictions.
Abstract: Two types of glass fibers having different lengths
(1/16" and 1/32") were added into rigid PVC foams to enhance the
dimensional stability of extruded rigid Polyvinyl Chloride (PVC)
foam at different concentrations (0-20 phr) using a single screw
profile extruder. PVC foam-glass fiber composites (PVC-GF) were
characterized for their dimensional stability, structural, thermal, and
mechanical properties. Experimental results show that the
dimensional stability, heat resistance, and storage modulus were
enhanced without compromising the tensile and flexural strengths of
the composites. Overall, foam composites which were prepared with
longer glass fibers exhibit better mechanical and thermal properties
than those prepared with shorter glass fibers due to higher
interlocking between the fibers and the foam cells, which result in
better load distribution in the matrix.
Abstract: In this paper, Least Mean Square (LMS) adaptive
noise reduction algorithm is proposed to enhance the speech signal
from the noisy speech. In this, the speech signal is enhanced by
varying the step size as the function of the input signal. Objective and
subjective measures are made under various noises for the proposed
and existing algorithms. From the experimental results, it is seen that
the proposed LMS adaptive noise reduction algorithm reduces Mean
square Error (MSE) and Log Spectral Distance (LSD) as compared to
that of the earlier methods under various noise conditions with
different input SNR levels. In addition, the proposed algorithm
increases the Peak Signal to Noise Ratio (PSNR) and Segmental SNR
improvement (ΔSNRseg) values; improves the Mean Opinion Score
(MOS) as compared to that of the various existing LMS adaptive
noise reduction algorithms. From these experimental results, it is
observed that the proposed LMS adaptive noise reduction algorithm
reduces the speech distortion and residual noise as compared to that
of the existing methods.
Abstract: This paper presents the hardware implemented and
validation for a special system to assist the unprofessional users of
car with back trailers. The system consists of two platforms; the front
car platform (C) and the trailer platform (T). The main objective is to
control the Trailer platform using the actuators found in the front
platform (c). The mobility of the platform (C) is investigated and
inverse and forward kinematics model is obtained for both platforms
(C) and (T).The system is simulated using Matlab M-file and the
simulation examples results illustrated the system performance. The
system is constructed with a hardware setup for the front and trailer
platform. The hardware experimental results and the simulated
examples outputs showed the validation of the hardware setup.
Abstract: The fuzzy composition of objects depicted in images
acquired through MR imaging or the use of bio-scanners has often
been a point of controversy for field experts attempting to effectively
delineate between the visualized objects. Modern approaches in
medical image segmentation tend to consider fuzziness as a
characteristic and inherent feature of the depicted object, instead of
an undesirable trait. In this paper, a novel technique for efficient
image retrieval in the context of images in which segmented objects
are either crisp or fuzzily bounded is presented. Moreover, the
proposed method is applied in the case of multiple, even conflicting,
segmentations from field experts. Experimental results demonstrate
the efficiency of the suggested method in retrieving similar objects
from the aforementioned categories while taking into account the
fuzzy nature of the depicted data.
Abstract: An active slat is developed to increase the lift and delay
the separation for a DU96-W180 airfoil. The active slat is a fixed slat
that can be closed, fully opened or intermittently opened by a rotating
vane depending on the need. Experimental results show that the active
slat has reduced the mean pressure and increased the mean velocity
on the suction side of the airfoil for all positive angles of attack,
indicating an increase of lift. The experimental data and numerical
simulations also show that the direction of actuator vane rotation can
influence the mixing of the flow streams on the suction side and
hence influence the aerodynamic performance.
Abstract: Tumor is an uncontrolled growth of tissues in any part
of the body. Tumors are of different types and they have different
characteristics and treatments. Brain tumor is inherently serious and
life-threatening because of its character in the limited space of the
intracranial cavity (space formed inside the skull). Locating the tumor
within MR (magnetic resonance) image of brain is integral part of the
treatment of brain tumor. This segmentation task requires
classification of each voxel as either tumor or non-tumor, based on
the description of the voxel under consideration. Many studies are
going on in the medical field using Markov Random Fields (MRF) in
segmentation of MR images. Even though the segmentation process
is better, computing the probability and estimation of parameters is
difficult. In order to overcome the aforementioned issues, Conditional
Random Field (CRF) is used in this paper for segmentation, along
with the modified artificial bee colony optimization and modified
fuzzy possibility c-means (MFPCM) algorithm. This work is mainly
focused to reduce the computational complexities, which are found in
existing methods and aimed at getting higher accuracy. The
efficiency of this work is evaluated using the parameters such as
region non-uniformity, correlation and computation time. The
experimental results are compared with the existing methods such as
MRF with improved Genetic Algorithm (GA) and MRF-Artificial
Bee Colony (MRF-ABC) algorithm.
Abstract: Key frame extraction methods select the most
representative frames of a video, which can be used in different areas
of video processing such as video retrieval, video summary, and video
indexing. In this paper we present a novel approach for extracting key
frames from video sequences. The frame is characterized uniquely by
his contours which are represented by the dominant blocks. These
dominant blocks are located on the contours and its near textures.
When the video frames have a noticeable changement, its dominant
blocks changed, then we can extracte a key frame. The dominant
blocks of every frame is computed, and then feature vectors are
extracted from the dominant blocks image of each frame and arranged
in a feature matrix. Singular Value Decomposition is used to calculate
sliding windows ranks of those matrices. Finally the computed ranks
are traced and then we are able to extract key frames of a video.
Experimental results show that the proposed approach is robust
against a large range of digital effects used during shot transition.
Abstract: Powder metallurgy (P/M) is the only economic way to
produce porous parts/products. P/M can produce near net shape parts
hence reduces wastage of raw material and energy, avoids various
machining operations. The most vital use of P/M is in production of
metallic filters and self lubricating bush bearings and siding surfaces.
The porosity of the part can be controlled by varying compaction
pressure, sintering temperature and composition of metal powder
mix. The present work is aimed for experimental analysis of friction
and wear properties of self lubricating copper and tin bush bearing.
Experimental results confirm that wear rate of sintered component
is lesser for components having 10% tin by weight percentage. Wear
rate increases for high tin percentage (experimented for 20% tin and
30% tin) at same sintering temperature. Experimental results also
confirms that wear rate of sintered component is also dependent on
sintering temperature, soaking period, composition of the preform,
compacting pressure, powder particle shape and size.
Interfacial friction between die and punch, between inter powder
particles, between die face and powder particle depends on
compaction pressure, powder particle size and shape, size and shape
of component which decides size & shape of die & punch, material of
die & punch and material of powder particles.
Abstract: This paper presents a study on Proportional Resonant
(PR) current control with additional PR harmonic compensators for
Grid Connected Photovoltaic (PV) Inverters. Both simulation and
experimental results will be presented. Testing was carried out on a
3kW Grid-Connected PV Inverter which was designed and
constructed for this research.
Abstract: A novel method to produce a fast high voltage solid
states switch using Insulated Gate Bipolar Transistors (IGBTs) is
presented for discharge-pumped gas lasers. The IGBTs are connected
in series to achieve a high voltage rating. An avalanche transistor is
used as the gate driver. The fast pulse generated by the avalanche
transistor quickly charges the large input capacitance of the IGBT,
resulting in a switch out of a fast high-voltage pulse. The switching
characteristic of fast-high voltage solid state switch has been estimated
in the multi-stage series-connected IGBT with the applied voltage of
several tens of kV. Electrical circuit diagram and the mythology of
fast-high voltage solid state switch as well as experimental results
obtained are presented.
Abstract: In this study, we aim to demonstrate a microgrid
system experimental simulation for an easy understanding of a
large-scale microgrid system. This model is required for industrial
training and learning environments. However, in order to create an
exact representation of a microgrid system, the laboratory-scale
system must fulfill the requirements of a grid-connected inverter, in
which power values are assigned to the system to cope with the
intermittent output from renewable energy sources. Aside from that,
during fluctuations in load capacity, the grid-connected system must
be able to supply power from the utility grid side and microgrid side in
a balanced manner. Therefore, droop control is installed in the
inverter’s control board to maintain a balanced power sharing in both
sides. This power control in a stand-alone condition and droop control
in a grid-connected condition must be implemented in order to
maintain a stabilized system. Based on the experimental results, power
control and droop control can both be applied in the system by
comparing the experimental and reference values.
Abstract: Microarray technology is universally used in the study
of disease diagnosis using gene expression levels. The main
shortcoming of gene expression data is that it includes thousands of
genes and a small number of samples. Abundant methods and
techniques have been proposed for tumor classification using
microarray gene expression data. Feature or gene selection methods
can be used to mine the genes that directly involve in the
classification and to eliminate irrelevant genes. In this paper
statistical measures like T-Statistics, Signal-to-Noise Ratio (SNR)
and F-Statistics are used to rank the genes. The ranked genes are used
for further classification. Particle Swarm Optimization (PSO)
algorithm and Shuffled Frog Leaping (SFL) algorithm are used to
find the significant genes from the top-m ranked genes. The Naïve
Bayes Classifier (NBC) is used to classify the samples based on the
significant genes. The proposed work is applied on Lung and Ovarian
datasets. The experimental results show that the proposed method
achieves 100% accuracy in all the three datasets and the results are
compared with previous works.
Abstract: In this paper, design of solid-state battery/supercapacitor emulator based on dc-dc boost converter is described.
The emulator mimics charging behavior of any storage device based
on a predefined behavior set by the user. The device is operated by a
two-level control structure: high-level emulating controller and low-
level input voltage controller. Simulation and experimental results are
shown to demonstrate the emulator operation.
Abstract: This study was conducted to evaluate the manganese
removal from aqueous solution using Banana peels activated carbon
(BPAC). Batch experiments have been carried out to determine the
influence of parameters such as pH, biosorbent dose, initial metal ion
concentrations and contact times on the biosorption process. From
these investigations, a significant increase in percentage removal of
manganese 97.4% is observed at pH value 5.0, biosorbent dose 0.8 g,
initial concentration 20 ppm, temperature 25 ± 2°C, stirring rate 200
rpm and contact time 2h. The equilibrium concentration and the
adsorption capacity at equilibrium of the experimental results were
fitted to the Langmuir and Freundlich isotherm models; the Langmuir
isotherm was found to well represent the measured adsorption data
implying BPAC had heterogeneous surface. A raw groundwater
samples were collected from Baharmos groundwater treatment plant
network at Embaba and Manshiet Elkanater City/District-Giza,
Egypt, for treatment at the best conditions that reached at first phase
by BPAC. The treatment with BPAC could reduce iron and
manganese value of raw groundwater by 91.4% and 97.1%,
respectively and the effect of the treatment process on the
microbiological properties of groundwater sample showed decrease
of total bacterial count either at 22°C or at 37°C to 85.7% and 82.4%,
respectively. Also, BPAC was characterized using SEM and FTIR
spectroscopy.
Abstract: Chloride resistance in Ultra High Performance
Concrete (UHPC) is determined in this paper. This work deals with
the one dimension chloride transport, which can be potentially
dangerous particularly for the durability of concrete structures. Risk
of reinforcement corrosion due to exposure to the concrete surface to
direct the action of chloride ions (mainly in the form de-icing salts or
groundwater) is dangerously increases. The measured data are
investigated depending on the depth of penetration of chloride ions
into the concrete structure. Comparative measurements with normal
strength concrete are done as well. The experimental results showed
that UHCP have improved resistance of chlorides penetration than
NSC and also chloride diffusion depth is significantly lower in
UHCP.
Abstract: In this study, the evaluation of thermal stability of the
micrometer-sized silica particle reinforced epoxy composite was
carried out through the measurement of thermal expansion coefficient
and Young’s modulus of the specimens. For all the specimens in this
study from the baseline to those containing 50 wt% silica filler, the
thermal expansion coefficients and the Young’s moduli were
gradually decreased down to 20% and increased up to 41%,
respectively. The experimental results were compared with fillervolume-
based simple empirical relations. The experimental results of
thermal expansion coefficients correspond with those of Thomas’s
model which is modified from the rule of mixture. However, the
measured result for Young’s modulus tends to be increased slightly.
The differences in increments of the moduli between experimental and
numerical model data are quite large.
Abstract: Voltage sags are the most common power quality
disturbance in the distribution system. It occurs due to the fault in the
electrical network or by the starting of a large induction motor and
this can be solved by using the custom power devices such as
Dynamic Voltage Restorer (DVR). In this paper DVR is proposed to
compensate voltage sags on critical loads dynamically. The DVR
consists of VSC, injection transformers, passive filters and energy
storage (lead acid battery). By injecting an appropriate voltage, the
DVR restores a voltage waveform and ensures constant load voltage.
The simulation and experimental results of a DVR using MATLAB
software shows clearly the performance of the DVR in mitigating
voltage sags.
Abstract: The paper describes the experiments and the kinetic
parameters calculus of the gasoil hydrofining. They are presented
experimental results of gasoil hidrofining using Mo and promoted
with Ni on aluminum support catalyst. The authors have adapted a
kinetic model gasoil hydrofining. Using this proposed kinetic model
and the experimental data they have calculated the parameters of the
model. The numerical calculus is based on minimizing the difference
between the experimental sulf concentration and kinetic model
estimation.