Abstract: Many water desalination technologies have been
developed but in general they are energy intensive and have high cost
and adverse environmental impact. Recently, adsorption technology
for water desalination has been investigated showing the potential of
using low temperature waste heat (50-85oC) thus reducing energy
consumption and CO2 emissions. This work mathematically
compares the performance of an adsorption cycle that produces two
useful effects namely, fresh water and cooling using two different
adsorbents, silica-gel and an advanced zeolite material AQSOA-ZO2,
produced by Mitsubishi plastics. It was found that at low chilled
water temperatures, typically below 20oC, the AQSOA-Z02 is more
efficient than silica-gel as the cycle can produce 5.8 m3 of fresh water
per day and 50.1 Rton of cooling per tonne of AQSOA-ZO2. Above
20oC silica-gel is still better as the cycle production reaches 8.4 m3
per day and 62.4 Rton per tonne of silica-gel. These results show the
potential of using the AQSOA-Z02 at low chilled water temperature
for water desalination and cooling applications.
Abstract: Advanced treatments such as forward osmosis (FO)
can be used to separate or reject nutrients from secondary treated
effluents. Forward osmosis uses the chemical potential across the
membrane, which is the osmotic pressure gradient, to induce water to
flow through the membrane from a feed solution (FS) into a draw
solution (DS). The performance of FO is affected by the membrane
characteristics, composition of the FS and DS, and operating
conditions. The aim of this study was to investigate the optimum
velocity and temperature for nutrient rejection and water flux
performance in FO treatments. MgCl2 was used as the DS in the FO
process. The results showed that higher cross flow velocities yielded
higher water fluxes. High rejection of nutrients was achieved by using
a moderate cross flow velocity at 0.25 m/s. Nutrient rejection was
insensitive to temperature variation, whereas water flux was
significantly impacted by it. A temperature of 25°C was found to be
good for nutrient rejection.
Abstract: Here, we study the characteristic feature of
conventional (ON-OFF keying) and soliton based transmission
system. We consider 20Gbps transmission system implemented with
Conventional Single Mode Fiber (C-SMF) to examine the role of
Gaussian pulse which is the characteristic of conventional
propagation and Hyperbolic-secant pulse which is the characteristic
of soliton propagation in it. We note the influence of these pulses
with respect to different dispersion lengths and soliton period in
conventional and soliton system respectively and evaluate the system
performance in terms of Quality factor. From the analysis, we could
prove that the soliton pulse has the consistent performance even for
long distance without dispersion compensation than the conventional
system as it is robust to dispersion. For the length of transmission of
200Km, soliton system yielded Q of 33.958 while the conventional
system totally exhausted with Q=0.
Abstract: Phthalates are ubiquitous environmental pollutants
well known because of their endocrine disrupting activity in human
organism. The aim of our study was, by biological monitoring,
investigate exposure to phthalates of Roma ethnicity group i.e.
children and adults from 5 families (n=29, average age 11.8 ± 7.6
years) living in western Slovakia. Additionally, we analysed some
associations between anthropometric measures, questionnaire data
i.e. socio-economic status, eating and drinking habits, practise of
personal care products and household conditions in comparison with
concentrations of phthalate metabolites. We used for analysis of urine
samples high performance liquid chromatography and tandem mass
spectrometry (HPLC-MS/MS) to determine concentrations of
phthalate metabolites monoethyl phthalate (MEP), mono-n-butyl
phthalate (MnBP), mono-iso-butyl phthalate (MiBP), mono(2-ethyl-
5-hydroxyhexyl) phthalate (5OH-MEHP), mono(2-ethyl-5-oxohexyl)
phthalate (5oxo-MEHP) and mono(2-etylhexyl) phthalate (MEHP).
Our results indicate that ethnicity, lower socioeconomic status and
different housing conditions in Roma population can affect urinary
concentration of phthalate metabolites.
Abstract: In the present study, RBF neural networks were used
for predicting the performance and emission parameters of a
biodiesel engine. Engine experiments were carried out in a 4 stroke
diesel engine using blends of diesel and Honge methyl ester as the
fuel. Performance parameters like BTE, BSEC, Tex and emissions
from the engine were measured. These experimental results were
used for ANN modeling.
RBF center initialization was done by random selection and by
using Clustered techniques. Network was trained by using fixed and
varying widths for the RBF units. It was observed that RBF results
were having a good agreement with the experimental results.
Networks trained by using clustering technique gave better results
than using random selection of centers in terms of reduced MRE and
increased prediction accuracy. The average MRE for the performance
parameters was 3.25% with the prediction accuracy of 98% and for
emissions it was 10.4% with a prediction accuracy of 80%.
Abstract: In this research article of modeling Underwater
Wireless Sensor Network Simulators, we provide a comprehensive
overview of the various currently available simulators used in UWSN
modeling. In this work, we compare their working environment,
software platform, simulation language, key features, limitations and
corresponding applications. Based on extensive experimentation and
performance analysis, we provide their efficiency for specific
applications. We have also provided guidelines for developing
protocols in different layers of the protocol stack, and finally these
parameters are also compared and tabulated. This analysis is
significant for researchers and designers to find the right simulator
for their research activities.
Abstract: This paper analyses the heat transfer performance and
fluid flow using different nanofluids in a square enclosure. The
energy equation and Navier-Stokes equation are solved numerically
using finite volume scheme. The effect of volume fraction
concentration on the enhancement of heat transfer has been studied
icorporating the Brownian motion; the influence of effective thermal
conductivity on the enhancement was also investigated for a range of
volume fraction concentration. The velocity profile for different
Rayleigh number. Water-Cu, water AL2O3 and water-TiO2 were
tested.
Abstract: In wastewater treatment processes, aeration introduces
air into a liquid. In these systems, air is introduced by different
devices submerged in the wastewater. Smaller bubbles result in more
bubble surface area per unit of volume and higher oxygen transfer
efficiency. Jet pumps are devices that use air bubbles and are widely
used in wastewater treatment processes. The principle of jet pumps is
their ability to transfer energy of one fluid, called primary or motive,
into a secondary fluid or gas. These pumps have no moving parts and
are able to work in remote areas under extreme conditions. The
objective of this work is to study experimentally the characteristics of
the jet pump and the size of air bubbles in the laboratory water tank.
The effect of flow rate ratio on pump performance is investigated in
order to have a better understanding about pump behavior under
various conditions, in order to determine the efficiency of receiving
air bubbles different sizes. The experiments show that we should take
care when increasing the flow rate ratio while seeking to decrease
bubble size in the outlet flow. This study will help improve and
extend the use of the jet pump in many practical applications.
Abstract: Due to the continuous increment of the load demand,
identification of weaker buses, improvement of voltage profile and
power losses in the context of the voltage stability problems has
become one of the major concerns for the larger, complex,
interconnected power systems. The objective of this paper is to
review the impact of Flexible AC Transmission System (FACTS)
controller in Wind generators connected electrical network for
maintaining voltage stability. Wind energy could be the growing
renewable energy due to several advantages. The influence of wind
generators on power quality is a significant issue; non uniform power
production causes variations in system voltage and frequency.
Therefore, wind farm requires high reactive power compensation; the
advances in high power semiconducting devices have led to the
development of FACTS. The FACTS devices such as for example
SVC inject reactive power into the system which helps in maintaining
a better voltage profile. The performance is evaluated on an IEEE 14
bus system, two wind generators are connected at low voltage buses
to meet the increased load demand and SVC devices are integrated at
the buses with wind generators to keep voltage stability. Power
flows, nodal voltage magnitudes and angles of the power network are
obtained by iterative solutions using MIPOWER.
Abstract: Many factors influence the educational outcome of
students. Some of these have been studied by researchers with many
emphasizing the role of students, schools, governments, peer groups
and so on. More often than not, some of these factors influencing the
academic achievement of the students have been traced back to
parents and family; being the primary platform on which learning not
only begins but is nurtured, encouraged and developed which later
transforms to the performance of the students. This study not only
explores parental and related factors that predict academic
achievement through the review of relevant literatures but also,
investigates the influence of parental background on the academic
achievement of senior secondary school students in Ibadan North
Local Government Area of Oyo State, Nigeria. As one of the criteria
of the quality of education, students’ academic achievement was
investigated because it is most often cited as an indicator of school
effectiveness by school authorities and educationists. The data
collection was done through interviews and use of well-structured
questionnaires administered to one hundred students (100) within the
target local government. This was statistically analysed and the result
showed that parents’ attitudes towards their children’s education had
significant effect(s) on students’ self-reporting of academic
achievement. However, such factors as parental education and socioeconomic
background had no significant relationship with the
students’ self-reporting of academic achievement.
Abstract: Margin-Based Principle has been proposed for a long
time, it has been proved that this principle could reduce the
structural risk and improve the performance in both theoretical
and practical aspects. Meanwhile, feed-forward neural network is
a traditional classifier, which is very hot at present with a deeper
architecture. However, the training algorithm of feed-forward neural
network is developed and generated from Widrow-Hoff Principle that
means to minimize the squared error. In this paper, we propose
a new training algorithm for feed-forward neural networks based
on Margin-Based Principle, which could effectively promote the
accuracy and generalization ability of neural network classifiers
with less labelled samples and flexible network. We have conducted
experiments on four UCI open datasets and achieved good results
as expected. In conclusion, our model could handle more sparse
labelled and more high-dimension dataset in a high accuracy while
modification from old ANN method to our method is easy and almost
free of work.
Abstract: The problems arising from unbalanced data sets
generally appear in real world applications. Due to unequal class
distribution, many researchers have found that the performance of
existing classifiers tends to be biased towards the majority class. The
k-nearest neighbors’ nonparametric discriminant analysis is a method
that was proposed for classifying unbalanced classes with good
performance. In this study, the methods of discriminant analysis are
of interest in investigating misclassification error rates for classimbalanced
data of three diabetes risk groups. The purpose of this
study was to compare the classification performance between
parametric discriminant analysis and nonparametric discriminant
analysis in a three-class classification of class-imbalanced data of
diabetes risk groups. Data from a project maintaining healthy
conditions for 599 employees of a government hospital in Bangkok
were obtained for the classification problem. The employees were
divided into three diabetes risk groups: non-risk (90%), risk (5%),
and diabetic (5%). The original data including the variables of
diabetes risk group, age, gender, blood glucose, and BMI were
analyzed and bootstrapped for 50 and 100 samples, 599 observations
per sample, for additional estimation of the misclassification error
rate. Each data set was explored for the departure of multivariate
normality and the equality of covariance matrices of the three risk
groups. Both the original data and the bootstrap samples showed nonnormality
and unequal covariance matrices. The parametric linear
discriminant function, quadratic discriminant function, and the
nonparametric k-nearest neighbors’ discriminant function were
performed over 50 and 100 bootstrap samples and applied to the
original data. Searching the optimal classification rule, the choices of
prior probabilities were set up for both equal proportions (0.33: 0.33:
0.33) and unequal proportions of (0.90:0.05:0.05), (0.80: 0.10: 0.10)
and (0.70, 0.15, 0.15). The results from 50 and 100 bootstrap samples
indicated that the k-nearest neighbors approach when k=3 or k=4 and
the defined prior probabilities of non-risk: risk: diabetic as 0.90:
0.05:0.05 or 0.80:0.10:0.10 gave the smallest error rate of
misclassification. The k-nearest neighbors approach would be
suggested for classifying a three-class-imbalanced data of diabetes
risk groups.
Abstract: Microscopic simulation tool kits allow for
consideration of the two processes of railway operations and the
previous timetable production. Block occupation conflicts on both
process levels are often solved by using defined train priorities. These
conflict resolutions (dispatching decisions) generate reactionary
delays to the involved trains. The sum of reactionary delays is
commonly used to evaluate the quality of railway operations, which
describes the timetable robustness. It is either compared to an
acceptable train performance or the delays are appraised
economically by linear monetary functions. It is impossible to
adequately evaluate dispatching decisions without a well-founded
objective function. This paper presents a new approach for the
evaluation of dispatching decisions. The approach uses mode choice
models and considers the behaviour of the end-customers. These
models evaluate the reactionary delays in more detail and consider
other competing modes of transport. The new approach pursues the
coupling of a microscopic model of railway operations with the
macroscopic choice mode model. At first, it will be implemented for
railway operations process but it can also be used for timetable
production. The evaluation considers the possibility for the customer
to interchange to other transport modes. The new approach starts to
look at rail and road, but it can also be extended to air travel. The
result of mode choice models is the modal split. The reactions by the
end-customers have an impact on the revenue of the train operating
companies. Different purposes of travel have different payment
reserves and tolerances towards late running. Aside from changes to
revenues, longer journey times can also generate additional costs.
The costs are either time- or track-specific and arise from required
changes to rolling stock or train crew cycles. Only the variable values
are summarised in the contribution margin, which is the base for the
monetary evaluation of delays. The contribution margin is calculated
for different possible solutions to the same conflict. The conflict
resolution is optimised until the monetary loss becomes minimal. The
iterative process therefore determines an optimum conflict resolution
by monitoring the change to the contribution margin. Furthermore, a
monetary value of each dispatching decision can also be derived.
Abstract: In this paper we propose a novel methodology for
extracting a road network and its nodes from satellite images of
Algeria country.
This developed technique is a progress of our previous research
works. It is founded on the information theory and the mathematical
morphology; the information theory and the mathematical
morphology are combined together to extract and link the road
segments to form a road network and its nodes.
We therefore have to define objects as sets of pixels and to study
the shape of these objects and the relations that exist between them.
In this approach, geometric and radiometric features of roads are
integrated by a cost function and a set of selected points of a crossing
road. Its performances were tested on satellite images of Algeria
country.
Abstract: Failure of typical seismic frames has been found by
plastic hinge occurring on beams section near column faces. On the
other hand, the seismic capacity of the frames can be enhanced if the
plastic hinges of the beams are shifted away from the column faces.
This paper presents detailing of reinforcements in the interior beam–
column connections aiming to relocate the plastic hinge of reinforced
concrete and precast concrete frames. Four specimens were tested
under quasi-static cyclic load including two monolithic specimens
and two precast specimens. For one monolithic specimen, typical
seismic reinforcement was provided and considered as a reference
specimen named M1. The other reinforced concrete frame M2
contained additional intermediate steel in the connection area
compared with the specimen M1. For the precast specimens,
embedded T-section steels in joint were provided, with and without
diagonal bars in the connection area for specimen P1 and P2,
respectively. The test results indicated the ductile failure with beam
flexural failure in monolithic specimen M1 and the intermediate steel
increased strength and improved joint performance of specimen M2.
For the precast specimens, cracks generated at the end of the steel
inserts. However, slipping of reinforcing steel lapped in top of the
beams was seen before yielding of the main bars leading to the brittle
failure. The diagonal bars in precast specimens P2 improved the
connection stiffness and the energy dissipation capacity.
Abstract: We evaluate the performance of a numerical method
for global optimization of expensive functions. The method is using a
response surface to guide the search for the global optimum. This
metamodel could be based on radial basis functions, kriging, or a
combination of different models. We discuss how to set the cyclic
parameters of the optimization method to get a balance between local
and global search. We also discuss the eventual problem with Runge
oscillations in the response surface.
Abstract: Cloud computing is the innovative and leading
information technology model for enabling convenient, on-demand
network access to a shared pool of configurable computing resources
that can be rapidly provisioned and released with minimal
management effort. In this paper, we aim at the development of
workflow management system for cloud computing platforms based
on our previous research on the dynamic allocation of the cloud
computing resources and its workflow process. We took advantage of
the HTML5 technology and developed web-based workflow interface.
In order to enable the combination of many tasks running on the cloud
platform in sequence, we designed a mechanism and developed an
execution engine for workflow management on clouds. We also
established a prediction model which was integrated with job queuing
system to estimate the waiting time and cost of the individual tasks on
different computing nodes, therefore helping users achieve maximum
performance at lowest payment. This proposed effort has the potential
to positively provide an efficient, resilience and elastic environment
for cloud computing platform. This development also helps boost user
productivity by promoting a flexible workflow interface that lets users
design and control their tasks' flow from anywhere.
Abstract: This work is the first dowel in a rather wide research
activity in collaboration with Euro Mediterranean Center for Climate
Changes, aimed at introducing scalable approaches in Ocean
Circulation Models. We discuss designing and implementation of
a parallel algorithm for solving the Variational Data Assimilation
(DA) problem on Graphics Processing Units (GPUs). The algorithm
is based on the fully scalable 3DVar DA model, previously proposed
by the authors, which uses a Domain Decomposition approach
(we refer to this model as the DD-DA model). We proceed with
an incremental porting process consisting of 3 distinct stages:
requirements and source code analysis, incremental development of
CUDA kernels, testing and optimization. Experiments confirm the
theoretic performance analysis based on the so-called scale up factor
demonstrating that the DD-DA model can be suitably mapped on
GPU architectures.
Abstract: The structures obtained with the use of sandwich
technologies combine low weight with high energy absorbing
capacity and load carrying capacity. Hence, there is a growing and
markedly interest in the use of sandwiches with aluminum foam core
because of very good properties such as flexural rigidity and energy
absorption capability. In the current investigation, the static threepoint
bending tests were carried out on the sandwiches with
aluminum foam core and glass fiber reinforced polymer (GFRP)
skins at different values of support span distances aiming the analyses
of their flexural performance. The influence of the core thickness and
the GFRP skin type was reported in terms of peak load and energy
absorption capacity. For this purpose, the skins with two different
types of fabrics which have same thickness value and the aluminum
foam core with two different thicknesses were bonded with a
commercial polyurethane based flexible adhesive in order to combine
the composite sandwich panels. The main results of the bending tests
are: force-displacement curves, peak force values, absorbed energy,
collapse mechanisms and the effect of the support span length and
core thickness. The results of the experimental study showed that the
sandwich with the skins made of S-Glass Woven fabrics and with the
thicker foam core presented higher mechanical values such as load
carrying and energy absorption capacities. The increment of the
support span distance generated the decrease of the mechanical
values for each type of panels, as expected, because of the inverse
proportion between the force and span length. The most common
failure types of the sandwiches are debonding of the lower skin and
the core shear. The obtained results have particular importance for
applications that require lightweight structures with a high capacity
of energy dissipation, such as the transport industry (automotive,
aerospace, shipbuilding and marine industry), where the problems of
collision and crash have increased in the last years.
Abstract: This paper investigates the benefits of deliberately
unbalancing both operation time means (MTs) and unreliability
(failure and repair rates) for non-automated production lines. The
lines were simulated with various line lengths, buffer capacities,
degrees of imbalance and patterns of MT and unreliability imbalance.
Data on two performance measures, namely throughput (TR) and
average buffer level (ABL) were gathered, analyzed and compared to
a balanced line counterpart. A number of conclusions were made
with respect to the ranking of configurations, as well as to the
relationships among the independent design parameters and the
dependent variables. It was found that the best configurations are a
balanced line arrangement and a monotone decreasing MT order,
coupled with either a decreasing or a bowl unreliability configuration,
with the first generally resulting in a reduced TR and the second
leading to a lower ABL than those of a balanced line.