Abstract: A study was conducted in greenhouse environment to
determine the response of five tissue-cultured date palm cultivars, Al-
Ahamad, Nabusaif, Barhee, Khalas, and Kasab to irrigation water
salinity of 1.6, 5, 10, or 20 dS/ m. The salinity level of 1.6dS/m, was
used as a control. The effects of high salinity on plant survival were
manifested at 360 days after planting (DAP) onwards. Three
cultivars, Khalas, Kasab and Barhee were able to tolerate 10 dS/m
salinity level at 24 months after the start of study. Khalas tolerated
the highest salinity level of 20 dS/ m and 'Nabusaif' was found to be the
least tolerant cv. The average heights of palms and the number of
fronds were decreased with increasing salinity levels as time
progressed.
Abstract: In this work, we present a reliable framework to solve boundary value problems with particular significance in solid mechanics. These problems are used as mathematical models in deformation of beams. The algorithm rests mainly on a relatively new technique, the Variational Iteration Method. Some examples are given to confirm the efficiency and the accuracy of the method.
Abstract: Copper based composites reinforced with WC and Ti
particles were prepared using planetary ball-mill. The experiment
was designed by using Taguchi technique and milling was carried out
in an air for several hours. The powder was characterized before and
after milling using the SEM, TEM and X-ray for microstructure and
for possible new phases. Microstructures show that milled particles
size and reduction in particle size depend on many parameters. The
distance d between planes of atoms estimated from X-ray powder
diffraction data and TEM image. X-ray diffraction patterns of the
milled powder did not show clearly any new peak or energy shift, but
the TEM images show a significant change in crystalline structure of
corporate on titanium in the composites.
Abstract: This study investigates the performance of radial basis function networks (RBFN) in forecasting the monthly CO2 emissions of an electric power utility. We also propose a method for input variable selection. This method is based on identifying the general relationships between groups of input candidates and the output. The effect that each input has on the forecasting error is examined by removing all inputs except the variable to be investigated from its group, calculating the networks parameter and performing the forecast. Finally, the new forecasting error is compared with the reference model. Eight input variables were identified as the most relevant, which is significantly less than our reference model with 30 input variables. The simulation results demonstrate that the model with the 8 inputs selected using the method introduced in this study performs as accurate as the reference model, while also being the most parsimonious.
Abstract: Alcohol and water extracts of Cymbopogon citratus
was investigated for anti-bacterial properties and phytochemical
constituents. The extract was screened against four gram-negative
bacteria Escherichia coli, Klebsiella pneumoniae, Pseudomonas
aeruginosa, Proteus vulgaris) and two grampositive bacteria Bacillus
subtilis and Staphylococcus aureus at four different concentrations
(1:1, 1:5, 1:10 and 1:20) using disc diffusion method. The antibacterial
examination was by disc diffusion techniques, while the
photochemical constituents were investigated using standard
chemical methods. Results showed that the extracts inhibited the
growth of standard and local strains of the organisms used. The
treatments were significantly different (P = 0.05). The minimum
inhibitory concentration of the extracts against the tested
microorganisms ranged between 150mg/ml and 50mg/ml. The
alcohol extracts were found to be generally more effective than the
water extract. The photochemical analysis revealed the presence of
alkaloids and phenol but absence of cardiac and cyanogenic
glycosides. The presence of alkaloid and phenols were inferred as
being responsible for the anti-bacterial properties of the extracts.
Abstract: Dynamics of laser radiation – metal target interaction
in water at 1064 nm by applying Mach-Zehnder interference
technique was studied. The mechanism of generating the well
developed regime of evaporation of a metal surface and a spherical
shock wave in water is proposed. Critical intensities of the NIR for
the well developed evaporation of silver and gold targets were
determined. Dynamics of shock waves was investigated for earlier
(dozens) and later (hundreds) nanoseconds of time. Transparent
expanding plasma-vapor-compressed water object was visualized and
measured. The thickness of compressed layer of water and pressures
behind the front of a shock wave for later time delays were obtained
from the optical treatment of interferograms.
Abstract: The steady mixed convection boundary layer flow from
a vertical cone in a porous medium filled with a nanofluid is
numerically investigated using different types of nanoparticles as Cu
(copper), Al2O3 (alumina) and TiO2 (titania). The boundary value
problem is solved by using the shooting technique by reducing it
into an ordinary differential equation. Results of interest for the local
Nusselt number with various values of the constant mixed convection
parameter and nanoparticle volume fraction parameter are evaluated.
It is found that dual solutions exist for a certain range of mixed
convection parameter.
Abstract: In the world of Peer-to-Peer (P2P) networking
different protocols have been developed to make the resource sharing
or information retrieval more efficient. The SemPeer protocol is a
new layer on Gnutella that transforms the connections of the nodes
based on semantic information to make information retrieval more
efficient. However, this transformation causes high clustering in the
network that decreases the number of nodes reached, therefore the
probability of finding a document is also decreased. In this paper we
describe a mathematical model for the Gnutella and SemPeer
protocols that captures clustering-related issues, followed by a
proposition to modify the SemPeer protocol to achieve moderate
clustering. This modification is a sort of link management for the
individual nodes that allows the SemPeer protocol to be more
efficient, because the probability of a successful query in the P2P
network is reasonably increased. For the validation of the models, we
evaluated a series of simulations that supported our results.
Abstract: Software project effort estimation is frequently seen
as complex and expensive for individual software engineers.
Software production is in a crisis. It suffers from excessive costs.
Software production is often out of control. It has been suggested that
software production is out of control because we do not measure.
You cannot control what you cannot measure. During last decade, a
number of researches on cost estimation have been conducted. The
metric-set selection has a vital role in software cost estimation
studies; its importance has been ignored especially in neural network
based studies. In this study we have explored the reasons of those
disappointing results and implemented different neural network
models using augmented new metrics. The results obtained are
compared with previous studies using traditional metrics. To be able
to make comparisons, two types of data have been used. The first
part of the data is taken from the Constructive Cost Model
(COCOMO'81) which is commonly used in previous studies and the
second part is collected according to new metrics in a leading
international company in Turkey. The accuracy of the selected
metrics and the data samples are verified using statistical techniques.
The model presented here is based on Multi-Layer Perceptron
(MLP). Another difficulty associated with the cost estimation studies
is the fact that the data collection requires time and care. To make a
more thorough use of the samples collected, k-fold, cross validation
method is also implemented. It is concluded that, as long as an
accurate and quantifiable set of metrics are defined and measured
correctly, neural networks can be applied in software cost estimation
studies with success
Abstract: One of the main trouble in a steel strip manufacturing
line is the breakage of whatever weld carried out between steel coils,
that are used to produce the continuous strip to be processed. A weld
breakage results in a several hours stop of the manufacturing line. In
this process the damages caused by the breakage must be repaired.
After the reparation and in order to go on with the production it will
be necessary a restarting process of the line. For minimizing this
problem, a human operator must inspect visually and manually each
weld in order to avoid its breakage during the manufacturing process.
The work presented in this paper is based on the Bayesian decision
theory and it presents an approach to detect, on real-time, steel strip
defective welds. This approach is based on quantifying the tradeoffs
between various classification decisions using probability and the
costs that accompany such decisions.
Abstract: The present study was designed to test the influence
of confirmed expectations, perceived usefulness and perceived
competence on e-learning satisfaction among university teachers. A
questionnaire was completed by 125 university teachers from 12
different universities in Norway. We found that 51% of the variance
in university teachers- satisfaction with e-learning could be explained
by the three proposed antecedents. Perceived usefulness seems to be
the most important predictor of teachers- satisfaction with e-learning.
Abstract: Clustering is the process of subdividing an input data set into a desired number of subgroups so that members of the same subgroup are similar and members of different subgroups have diverse properties. Many heuristic algorithms have been applied to the clustering problem, which is known to be NP Hard. Genetic algorithms have been used in a wide variety of fields to perform clustering, however, the technique normally has a long running time in terms of input set size. This paper proposes an efficient genetic algorithm for clustering on very large data sets, especially on image data sets. The genetic algorithm uses the most time efficient techniques along with preprocessing of the input data set. We test our algorithm on both artificial and real image data sets, both of which are of large size. The experimental results show that our algorithm outperforms the k-means algorithm in terms of running time as well as the quality of the clustering.
Abstract: This article is dedicated to development of
mathematical models for determining the dynamics of
concentration of hazardous substances in urban turbulent
atmosphere. Development of the mathematical models implied
taking into account the time-space variability of the fields of
meteorological items and such turbulent atmosphere data as vortex
nature, nonlinear nature, dissipativity and diffusivity. Knowing the
turbulent airflow velocity is not assumed when developing the
model. However, a simplified model implies that the turbulent and
molecular diffusion ratio is a piecewise constant function that
changes depending on vertical distance from the earth surface.
Thereby an important assumption of vertical stratification of urban
air due to atmospheric accumulation of hazardous substances
emitted by motor vehicles is introduced into the mathematical
model. The suggested simplified non-linear mathematical model of
determining the sought exhaust concentration at a priori unknown
turbulent flow velocity through non-degenerate transformation is
reduced to the model which is subsequently solved analytically.
Abstract: This paper considers various channels of gammaquantum
generation via an ultra-short high-power laser pulse
interaction with different targets.We analyse the possibilities to create
a pulsed gamma-radiation source using laser triggering of some
nuclear reactions and isomer targets. It is shown that sub-MeV
monochromatic short pulse of gamma-radiation can be obtained with
pulse energy of sub-mJ level from isomer target irradiated by intense
laser pulse. For nuclear reaction channel in light- atom materials, it is
shown that sub-PW laser pulse gives rise to formation about million
gamma-photons of multi-MeV energy.
Abstract: University websites are considered as one of the brand primary touch points for multiple stakeholders, but most of them did not have great designs to create favorable impressions. Some of the elements that web designers should carefully consider are the appearance, the content, the functionality, usability and search engine optimization. However, priority should be placed on website simplicity and negative space. In terms of content, previous research suggests that universities should include reputation, learning environment, graduate career prospects, image destination, cultural integration, and virtual tour on their websites. The study examines how top 200 world ranking science and technology-based universities present their brands online and whether the websites capture the content dimensions. Content analysis of the websites revealed that the top ranking universities captured these dimensions at varying degree. Besides, the UK-based university had better priority on website simplicity and negative space compared to the Malaysian-based university.
Abstract: An approach to develop the FPGA of a flexible key
RSA encryption engine that can be used as a standard device in the
secured communication system is presented. The VHDL modeling of
this RSA encryption engine has the unique characteristics of
supporting multiple key sizes, thus can easily be fit into the systems
that require different levels of security. A simple nested loop addition
and subtraction have been used in order to implement the RSA
operation. This has made the processing time faster and used
comparatively smaller amount of space in the FPGA. The hardware
design is targeted on Altera STRATIX II device and determined that
the flexible key RSA encryption engine can be best suited in the
device named EP2S30F484C3. The RSA encryption implementation
has made use of 13,779 units of logic elements and achieved a clock
frequency of 17.77MHz. It has been verified that this RSA
encryption engine can perform 32-bit, 256-bit and 1024-bit
encryption operation in less than 41.585us, 531.515us and 790.61us
respectively.
Abstract: Intrusion Detection System is significant in network
security. It detects and identifies intrusion behavior or intrusion
attempts in a computer system by monitoring and analyzing the
network packets in real time. In the recent year, intelligent algorithms
applied in the intrusion detection system (IDS) have been an
increasing concern with the rapid growth of the network security.
IDS data deals with a huge amount of data which contains irrelevant
and redundant features causing slow training and testing process,
higher resource consumption as well as poor detection rate. Since the
amount of audit data that an IDS needs to examine is very large even
for a small network, classification by hand is impossible. Hence, the
primary objective of this review is to review the techniques prior to
classification process suit to IDS data.
Abstract: Performance of a limited Round-Robin (RR) rule is
studied in order to clarify the characteristics of a realistic sharing
model of a processor. Under the limited RR rule, the processor
allocates to each request a fixed amount of time, called a quantum, in a
fixed order. The sum of the requests being allocated these quanta is
kept below a fixed value. Arriving requests that cannot be allocated
quanta because of such a restriction are queued or rejected. Practical
performance measures, such as the relationship between the mean
sojourn time, the mean number of requests, or the loss probability and
the quantum size are evaluated via simulation. In the evaluation, the
requested service time of an arriving request is converted into a
quantum number. One of these quanta is included in an RR cycle,
which means a series of quanta allocated to each request in a fixed
order. The service time of the arriving request can be evaluated using
the number of RR cycles required to complete the service, the number
of requests receiving service, and the quantum size. Then an increase
or decrease in the number of quanta that are necessary before service is
completed is reevaluated at the arrival or departure of other requests.
Tracking these events and calculations enables us to analyze the
performance of our limited RR rule. In particular, we obtain the most
suitable quantum size, which minimizes the mean sojourn time, for the
case in which the switching time for each quantum is considered.
Abstract: Robot manipulators are highly coupled nonlinear
systems, therefore real system and mathematical model of dynamics
used for control system design are not same. Hence, fine-tuning of
controller is always needed. For better tuning fast simulation speed
is desired. Since, Matlab incorporates LAPACK to increase the speed
and complexity of matrix computation, dynamics, forward and
inverse kinematics of PUMA 560 is modeled on Matlab/Simulink in
such a way that all operations are matrix based which give very less
simulation time. This paper compares PID parameter tuning using
Genetic Algorithm, Simulated Annealing, Generalized Pattern Search
(GPS) and Hybrid Search techniques. Controller performances for all
these methods are compared in terms of joint space ITSE and
cartesian space ISE for tracking circular and butterfly trajectories.
Disturbance signal is added to check robustness of controller. GAGPS
hybrid search technique is showing best results for tuning PID
controller parameters in terms of ITSE and robustness.
Abstract: In this study, lipase production has been investigated
using submerge fermentation by Aspergillus niger in Kilka fish oil as
main substrate. The Taguchi method with an L9 orthogonal array
design was used to investigate the effect of parameters and their
levels on lipase productivity. The optimum conditions for Kilka fish
oil concentration, incubation temperature and pH were obtained 3
gr./ml 35°C and 7, respectively. The amount of lipase activity in
optimum condition was obtained 4.59IU/ml. By comparing this
amount with the amount of productivity in the olive oil medium
based on the cost of each medium, it was that using Kilka fish oil is
84% economical. Therefore Kilka fish oil can be used as an
economical and suitable substrate in the lipase production and
industrial usages.