Abstract: A multilayer self organizing neural neural network
(MLSONN) architecture for binary object extraction, guided by a beta
activation function and characterized by backpropagation of errors
estimated from the linear indices of fuzziness of the network output
states, is discussed. Since the MLSONN architecture is designed to
operate in a single point fixed/uniform thresholding scenario, it does
not take into cognizance the heterogeneity of image information in
the extraction process. The performance of the MLSONN architecture
with representative values of the threshold parameters of the beta
activation function employed is also studied. A three layer bidirectional
self organizing neural network (BDSONN) architecture
comprising fully connected neurons, for the extraction of objects from
a noisy background and capable of incorporating the underlying image
context heterogeneity through variable and adaptive thresholding,
is proposed in this article. The input layer of the network architecture
represents the fuzzy membership information of the image scene to
be extracted. The second layer (the intermediate layer) and the final
layer (the output layer) of the network architecture deal with the self
supervised object extraction task by bi-directional propagation of the
network states. Each layer except the output layer is connected to the
next layer following a neighborhood based topology. The output layer
neurons are in turn, connected to the intermediate layer following
similar topology, thus forming a counter-propagating architecture
with the intermediate layer. The novelty of the proposed architecture
is that the assignment/updating of the inter-layer connection weights
are done using the relative fuzzy membership values at the constituent
neurons in the different network layers. Another interesting feature
of the network lies in the fact that the processing capabilities of
the intermediate and the output layer neurons are guided by a beta
activation function, which uses image context sensitive adaptive
thresholding arising out of the fuzzy cardinality estimates of the
different network neighborhood fuzzy subsets, rather than resorting to
fixed and single point thresholding. An application of the proposed
architecture for object extraction is demonstrated using a synthetic
and a real life image. The extraction efficiency of the proposed
network architecture is evaluated by a proposed system transfer index
characteristic of the network.
Abstract: In a transcutanious inductive coupling of a biomedical
implant, a new formula is given for the study of the Radio Frequency
power attenuation by the biological tissue. The loss of the signal
power is related to its interaction with the biological tissue and the
composition of this one. A confrontation with the practical
measurements done with a synthetic muscle into a Faraday cage,
allowed a checking of the obtained theoretical results. The
supply/data transfer systems used in the case of biomedical implants,
can be well dimensioned by taking in account this type of power
attenuation.
Abstract: Science parks are often established to drive regional
economic growth, especially in countries with emerging economies.
However, mixed findings regarding the performances of science park
firms are found in the literature. This study tries to explain these
mixed findings by taking a relational approach and exploring
(un)intended knowledge transfers between new technology-based
firms (NTBFs) in the emerging South African economy. Moreover,
the innovation outcomes of these NTBFs are examined by using a
multi-dimensional construct. Results show that science park location
plays a significant role in explaining innovative sales, but is
insignificant when a different indicator of innovation outcomes is
used. Furthermore, only for innovations that are new to the firms,
both science park location and intended knowledge transfer via
informal business relationships have a positive impact; whereas
social relationships have a negative impact.
Abstract: Bubble columns have a variety of applications in
absorption, bio-reactions, catalytic slurry reactions, and coal
liquefaction; because they are simple to operate, provide good heat
and mass transfer, having less operational cost. The use of
Computational Fluid Dynamics (CFD) for bubble column becomes
important, since it can describe the fluid hydrodynamics on both local
and global scale. Euler- Euler two-phase fluid model has been used to
simulate two-phase (air and water) transient up-flow in bubble
column (15cm diameter) using FLUENT6.3. These simulations and
experiments were operated over a range of superficial gas velocities
in the bubbly flow and churn turbulent regime (1 to16 cm/s) at
ambient conditions. Liquid velocity was varied from 0 to 16cm/s. The
turbulence in the liquid phase is described using the standard k-ε
model. The interactions between the two phases are described
through drag coefficient formulations (Schiller Neumann). The
objectives are to validate CFD simulations with experimental data,
and to obtain grid-independent numerical solutions. Quantitatively
good agreements are obtained between experimental data for hold-up
and simulation values. Axial liquid velocity profiles and gas holdup
profiles were also obtained for the simulation.
Abstract: Thermal conductivity is an important characteristic of
a nanofluid in laminar flow heat transfer. This paper presents an
improved model for the prediction of the effective thermal
conductivity of nanofluids based on dimensionless groups. The
model expresses the thermal conductivity of a nanofluid as a function
of the thermal conductivity of the solid and liquid, their volume
fractions and particle size. The proposed model includes a parameter
which accounts for the interfacial shell, brownian motion, and
aggregation of particle. The validation of the model is verified by
applying the results obtained by the experiments of Tio2-water and
Al2o3-water nanofluids.
Abstract: The tubes in an Ammonia primary reformer furnace
operate close to the limits of materials technology in terms of the
stress induced as a result of very high temperatures, combined with
large differential pressures across the tube wall. Operation at tube
wall temperatures significantly above design can result in a rapid
increase in the number of tube failures, since tube life is very
sensitive to the absolute operating temperature of the tube. Clearly it
is important to measure tube wall temperatures accurately in order to
prevent premature tube failure by overheating.. In the present study,
the catalyst tubes in an Ammonia primary reformer has been modeled
taking into consideration heat, mass and momentum transfer as well
as reformer characteristics.. The investigations concern the effects of
tube characteristics and superficial tube wall temperatures on of the
percentage of heat flux, unconverted methane and production of
Hydrogen for various values of steam to carbon ratios. The results
show the impact of catalyst tubes length and diameters on the
performance of operating parameters in ammonia primary reformers.
Abstract: In this paper, the melting of a semi-infinite body as a
result of a moving laser beam has been studied. Because the Fourier
heat transfer equation at short times and large dimensions does not
have sufficient accuracy; a non-Fourier form of heat transfer
equation has been used. Due to the fact that the beam is moving in x
direction, the temperature distribution and the melting pool shape are
not asymmetric. As a result, the problem is a transient threedimensional
problem. Therefore, thermophysical properties such as
heat conductivity coefficient, density and heat capacity are functions
of temperature and material states. The enthalpy technique, used for
the solution of phase change problems, has been used in an explicit
finite volume form for the hyperbolic heat transfer equation. This
technique has been used to calculate the transient temperature
distribution in the semi-infinite body and the growth rate of the melt
pool. In order to validate the numerical results, comparisons were
made with experimental data. Finally, the results of this paper were
compared with similar problem that has used the Fourier theory. The
comparison shows the influence of infinite speed of heat propagation
in Fourier theory on the temperature distribution and the melt pool
size.
Abstract: As a result of traffic congestion caused by sightseeing
and shuttle buses using park-and-ride parking lot near sightseeing spot,
the waiting time for tourist increases. In this paper, when bus parking
lot near sightseeing spot are overcrowded and full, a model for tourists
getting off a bus on a congested road and transfer to the sightseeing
spot by foot is proposed and verified. A model of getting off a bus on a
congested road when the sightseeing parking lot is overcrowded was
considered by the case analysis. As a result, effectiveness of the model
of getting off a bus on a congested road could be quantitatively
verified for times when parking capacity is exceeded and the bus
parking lot next to the sightseeing spot is overcrowded.
Abstract: To make use of the limited amounts of water in arid
region, the Iranians developed man-made underground water
channels called qanats (kanats) .In fact, qanats may be considered as
the first long-distance water transfer system. Qanats are an ancient
water transfer system found in arid regions wherein groundwater
from mountainous areas, aquifers and sometimes from rivers, was
brought to points of re-emergence such as an oasis, through one or
more underground tunnels. The tunnels, many of which were
kilometers in length, had designed for slopes to provide gravitational
flow. The tunnels allowed water to drain out to the surface by gravity
to supply water to lower and flatter agricultural land.
Qanats have been an ancient, sustainable system facilitating the
harvesting of water for centuries in Iran, and more than 35 additional
countries of the world such as India, Arabia, Egypt, North Africa,
Spain and even to New world.
There are about 22000 qanats in Iran with 274000 kilometers of
underground conduits all built by manual labor. The amount of
water of the usable qanats of Iran produce is altogether 750 to
1000 cubic meter per second. The longest chain of qanat is
situated in Gonabad region in Khorasan province. It is 70
kilometers long. Qanats are renewable water supply systems that
have sustained agricultural settlement on the Iranian plateau for
millennia. The great advantages of Qanats are no evaporation
during transit, little seepage , no raising of the water- table and no
pollution in the area surrounding the conduits. Qanat systems
have a profound influence on the lives of the water users in Iran, and
conform to Iran-s climate. Qanat allows those living in a desert
environment adjacent to a mountain watershed to create a large oasis
in an otherwise stark environment.
This paper explains qanats structure designs, their history,
objectives causing their creation, construction materials, locations
and their importance in different times, as well as their present
sustainable role in Iran.
Abstract: This paper proposes a new version of the Particle
Swarm Optimization (PSO) namely, Modified PSO (MPSO) for
model order formulation of Single Input Single Output (SISO) linear
time invariant continuous systems. In the General PSO, the
movement of a particle is governed by three behaviors namely
inertia, cognitive and social. The cognitive behavior helps the
particle to remember its previous visited best position. In Modified
PSO technique split the cognitive behavior into two sections like
previous visited best position and also previous visited worst
position. This modification helps the particle to search the target very
effectively. MPSO approach is proposed to formulate the higher
order model. The method based on the minimization of error
between the transient responses of original higher order model and
the reduced order model pertaining to the unit step input. The results
obtained are compared with the earlier techniques utilized, to validate
its ease of computation. The proposed method is illustrated through
numerical example from literature.
Abstract: Laser interferometric methods have been utilized for the measurement of natural convection heat transfer from a heated vertical flat plate, in the investigation presented here. The study mainly aims at comparing two different fringe orientations in the wedge fringe setting of Mach-Zehnder interferometer (MZI), used for the measurements. The interference fringes are set in horizontal and vertical orientations with respect to the heated surface, and two different fringe analysis methods, namely the stepping method and the method proposed by Naylor and Duarte, are used to obtain the heat transfer coefficients. The experimental system is benchmarked with theoretical results, thus validating its reliability in heat transfer measurements. The interference fringe patterns are analyzed digitally using MATLAB 7 and MOTIC Plus softwares, which ensure improved efficiency in fringe analysis, hence reducing the errors associated with conventional fringe tracing. The work also discuss the relative merits and limitations of the two methods used.
Abstract: For many industrial applications plate heat
exchangers are demonstrating a large superiority over the
other types of heat exchangers. The efficiency of such a
device depends on numerous factors the effect of which needs
to be analysed and accurately evaluated.
In this paper we present a theoretical analysis of a cocurrent
plate heat exchanger and the results of its numerical
simulation.
Knowing the hot and the cold fluid streams inlet temperatures,
the respective heat capacities mCp
and the value of the
overall heat transfer coefficient, a 1-D mathematical model
based on the steady flow energy balance for a differential
length of the device is developed resulting in a set of N first
order differential equations with boundary conditions where N
is the number of channels.For specific heat exchanger
geometry and operational parameters, the problem is
numerically solved using the shooting method.
The simulation allows the prediction of the temperature
map in the heat exchanger and hence, the evaluation of its
performances. A parametric analysis is performed to evaluate
the influence of the R-parameter on the e-NTU values. For
practical purposes effectiveness-NTU graphs are elaborated
for specific heat exchanger geometry and different operating
conditions.
Abstract: Aim of this study is to evaluate a new three-equation turbulence model applied to flow and heat transfer through a pipe. Uncertainty is approximated by comparing with published direct numerical simulation results for fully-developed flow. Error in the mean axial velocity, temperature, friction, and heat transfer is found to be negligible.
Abstract: Internet Protocol version 4 (IPv4) address is decreasing and a rapid transition method to the next generation IP address (IPv6) should be established. This study aims to evaluate and select the best performance of the IPv6 address network transitionmechanisms, such as IPv4/IPv6 dual stack, transport Relay Translation (TRT) and Reverse Proxy with additional features. It is also aim to prove that faster access can be done while ensuring optimal usage of available resources used during the test and actual implementation. This study used two test methods such asInternet Control Message Protocol (ICMP)ping and ApacheBenchmark (AB) methodsto evaluate the performance.Performance metrics for this study include aspects ofaverageaccessin one second,time takenfor singleaccess,thedata transfer speed and the costof additional requirements.Reverse Proxy with Caching featureis the most efficientmechanism because of it simpler configurationandthe best performerfrom the test conducted.
Abstract: Investigation of soil properties like Cation Exchange
Capacity (CEC) plays important roles in study of environmental
reaserches as the spatial and temporal variability of this property
have been led to development of indirect methods in estimation of
this soil characteristic. Pedotransfer functions (PTFs) provide an
alternative by estimating soil parameters from more readily available
soil data. 70 soil samples were collected from different horizons of
15 soil profiles located in the Ziaran region, Qazvin province, Iran.
Then, multivariate regression and neural network model (feedforward
back propagation network) were employed to develop a
pedotransfer function for predicting soil parameter using easily
measurable characteristics of clay and organic carbon. The
performance of the multivariate regression and neural network model
was evaluated using a test data set. In order to evaluate the models,
root mean square error (RMSE) was used. The value of RMSE and
R2 derived by ANN model for CEC were 0.47 and 0.94 respectively,
while these parameters for multivariate regression model were 0.65
and 0.88 respectively. Results showed that artificial neural network
with seven neurons in hidden layer had better performance in
predicting soil cation exchange capacity than multivariate regression.
Abstract: This research project aims to investigate difference in
relative rates concerning phosphoryl transfer relevant to biological
catalysis of DNA and RNA in the pH-independent reactions.
Activated Models of DNA and RNA for alkyl-aryl phosphate diesters
(with 4-nitrophenyl as a good leaving group) have successfully been
prepared to gather kinetic parameters. Eyring plots for the pH–
independent hydrolysis of 1 and 2 were established at different
temperatures in the range 100–160 °C. These measurements have
been used to provide a better estimate for the difference in relative
rates between the reactivity of DNA and RNA cleavage. Eyring plot
gave an extrapolated rate of kH2O = 1 × 10-10 s -1 for 1 (RNA model)
and 2 (DNA model) at 25°C. Comparing the reactivity of RNA
model and DNA model shows that the difference in relative rates in
the pH-independent reactions is surprisingly very similar at 25°. This
allows us to obtain chemical insights into how biological catalysts
such as enzymes may have evolved to perform their current
functions.
Abstract: Phase locked loops in 10 Gb/s and faster data links are
low phase noise devices. Characterization of their phase jitter
transfer functions is difficult because the intrinsic noise of the PLLs
is comparable to the phase noise of the reference clock signal. The
problem is solved by using a linear model to account for the intrinsic
noise. This study also introduces a novel technique for measuring the
transfer function. It involves the use of the reference clock as a
source of wideband excitation, in contrast to the commonly used
sinusoidal excitations at discrete frequencies. The data reported here
include the intrinsic noise of a PLL for 10 Gb/s links and the jitter
transfer function of a PLL for 12.8 Gb/s links. The measured transfer
function suggests that the PLL responded like a second order linear
system to a low noise reference clock.
Abstract: This paper presents performance analysis of the
Evolutionary Programming-Artificial Neural Network (EPANN)
based technique to optimize the architecture and training parameters
of a one-hidden layer feedforward ANN model for the prediction of
energy output from a grid connected photovoltaic system. The ANN
utilizes solar radiation and ambient temperature as its inputs while the
output is the total watt-hour energy produced from the grid-connected
PV system. EP is used to optimize the regression performance of the
ANN model by determining the optimum values for the number of
nodes in the hidden layer as well as the optimal momentum rate and
learning rate for the training. The EPANN model is tested using two
types of transfer function for the hidden layer, namely the tangent
sigmoid and logarithmic sigmoid. The best transfer function, neural
topology and learning parameters were selected based on the highest
regression performance obtained during the ANN training and testing
process. It is observed that the best transfer function configuration for
the prediction model is [logarithmic sigmoid, purely linear].
Abstract: This paper has two main ideas. Firstly, it describes Evans and Wurster-s concepts “the trade-off between reach and richness", and relates them to the impact of technology on the virtual markets. Authors Evans and Wurster see the transfer of information as a 'trade'off between richness and reach-. Reach refers to the number of people who share particular information, with Richness ['Rich'] being a more complex concept combining: bandwidth, customization, interactivity, reliability, security and currency. Traditional shopping limits the number of shops the shopper is able to visit due to time and other cost constraints; the time spent traveling consequently leaves the shopper with less time to evaluate the product. The paper concludes that although the Web provides Reach, offering Richness and the sense of community required for creating and sustaining relationships with potential clients could be difficult.
Abstract: Data gathering is an essential operation in wireless
sensor network applications. So it requires energy efficiency
techniques to increase the lifetime of the network. Similarly,
clustering is also an effective technique to improve the energy
efficiency and network lifetime of wireless sensor networks. In this
paper, an energy efficient cluster formation protocol is proposed with
the objective of achieving low energy dissipation and latency without
sacrificing application specific quality. The objective is achieved by
applying randomized, adaptive, self-configuring cluster formation
and localized control for data transfers. It involves application -
specific data processing, such as data aggregation or compression.
The cluster formation algorithm allows each node to make
independent decisions, so as to generate good clusters as the end.
Simulation results show that the proposed protocol utilizes minimum
energy and latency for cluster formation, there by reducing the
overhead of the protocol.