Abstract: Climate change will affect the hydrological cycle in
many different ways such as increase in evaporation and rainfalls.
There have been growing interests among researchers to identify the
nature of trends in historical rainfall data in many different parts of
the world. This paper examines the trends in annual maximum
rainfall data from 30 stations in New South Wales, Australia by using
two non-parametric tests, Mann-Kendall (MK) and Spearman’s Rho
(SR). Rainfall data were analyzed for fifteen different durations
ranging from 6 min to 3 days. It is found that the sub-hourly
durations (6, 12, 18, 24, 30 and 48 minutes) show statistically
significant positive (upward) trends whereas longer duration (subdaily
and daily) events generally show a statistically significant
negative (downward) trend. It is also found that the MK test and SR
test provide notably different results for some rainfall event durations
considered in this study. Since shorter duration sub-hourly rainfall
events show positive trends at many stations, the design rainfall data
based on stationary frequency analysis for these durations need to be
adjusted to account for the impact of climate change. These shorter
durations are more relevant to many urban development projects
based on smaller catchments having a much shorter response time.
Abstract: In structures, stress concentration is a factor of fatigue
fracture. Basically, the stress concentration is a phenomenon that
should be avoided. However, it is difficult to avoid the stress
concentration. Therefore, relaxation of the stress concentration is
important. The stress concentration arises from notches and circular
holes. There is a relaxation method that a composite patch covers a
notch and a circular hole. This relaxation method is used to repair
aerial wings, but it is not systematized. Composites are more
expensive than single materials. Accordingly, we propose the
relaxation method that a single material patch covers a notch and a
circular hole, and aim to systematize this relaxation method.
We performed FEA (Finite Element Analysis) about an object by
using a three-dimensional FEA model. The object was that a patch
adheres to a plate with a circular hole. And, a uniaxial tensile load acts
on the patched plate with a circular hole. In the three-dimensional FEA
model, it is not easy to model the adhesion layer. Basically, the yield
stress of the adhesive is smaller than that of adherents. Accordingly,
the adhesion layer gets to plastic deformation earlier than the adherents
under the yield load of adherents. Therefore, we propose the
three-dimensional FEA model which is applied a nonlinear elastic
region to the adhesion layer. The nonlinear elastic region was
calculated by a bilinear approximation. We compared the analysis
results with the tensile test results to confirm whether the analysis
model has usefulness. As a result, the analysis results agreed with the
tensile test results. And, we confirmed that the analysis model has
usefulness.
As a result that the three-dimensional FEA model was used to the
analysis, it was confirmed that an out-of-plane deformation occurred
to the patched plate with a circular hole. The out-of-plane deformation
causes stress increase of the patched plate with a circular hole.
Therefore, we investigated that the out-of-plane deformation affects
relaxation of the stress concentration in the plate with a circular hole
on this relaxation method. As a result, it was confirmed that the
out-of-plane deformation inhibits relaxation of the stress concentration
on the plate with a circular hole.
Abstract: In new energy development, wind power has boomed.
It is due to the proliferation of wind parks and their operation in
supplying the national electric grid with low cost and clean resources.
Hence, there is an increased need to establish a proactive
maintenance for wind turbine machines based on remote control and
monitoring. That is necessary with a real-time wireless connection in
offshore or inaccessible locations while the wired method has many
flaws. The objective of this strategy is to prolong wind turbine
lifetime and to increase productivity. The hardware of a remote
control and monitoring system for wind turbine parks is designed. It
takes advantage of GPRS or Wi-Max wireless module to collect data
measurements from different wind machine sensors through IP based
multi-hop communication. Computer simulations with Proteus ISIS
and OPNET software tools have been conducted to evaluate the
performance of the studied system. Study findings show that the
designed device is suitable for application in a wind park.
Abstract: Different services based on different switching
techniques in wireless networks leads to drastic changes in the
properties of network traffic. Because of these diversities in services,
network traffic is expected to undergo qualitative and quantitative
variations. Hence, assumption of traffic characteristics and the
prediction of network events become more complex for the wireless
networks. In this paper, the traffic characteristics have been studied
by collecting traces from the mobile switching centre (MSC). The
traces include initiation and termination time, originating node, home
station id, foreign station id. Traffic parameters namely, call interarrival
and holding times were estimated statistically. The results
show that call inter-arrival and distribution time in this wireless
network is heavy-tailed and follow gamma distributions. They are
asymptotically long-range dependent. It is also found that the call
holding times are best fitted with lognormal distribution. Based on
these observations, an analytical model for performance estimation is
also proposed.
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 family of multilevel inverter topology
with reduced number of power switches is presented. The proposed
inverter can generate both even and odd level. The proposed topology
is suitable for symmetric structure. The proposed symmetric inverter
results in reduction of power switches, power diode and gate driver
circuits and also it may further minimize the installation area and
cost. To prove the superiority of proposed topology is compared with
conventional topologies. The performance of this symmetric
multilevel inverter has been tested by computer based simulation and
prototype based experimental setup for nine-level inverter is
developed and results are verified.
Abstract: Most quality models have defined usability as a
significant factor that leads to improving product acceptability,
increasing user satisfaction, improving product reliability, and also
financially benefitting companies. Usability is also the best factor that
balances both the technical and human aspects of a software product,
which is an important aspect in defining quality during software
development process. A usability risk consist risk factors that could
impact the usability of a software product thereby contributing to
negative user experiences and causing a possible software product
failure. Hence, it is important to mitigate and reduce usability risks in
the software development process itself. By managing possible
usability risks in software development process, failure of software
product could be reduced. Therefore, this research uses the Delphi
method to identify mitigation plans for reducing potential usability
risks. The Delphi method is conducted with seven experts from the
field of risk management and software development.
Abstract: Climate change will affect various aspects of
hydrological cycle such as rainfall. A change in rainfall will affect
flood magnitude and frequency in future which will affect the design
and operation of hydraulic structures. In this paper, trends in subhourly,
sub-daily, and daily extreme rainfall events from 18 rainfall
stations located in Tasmania, Australia are examined. Two nonparametric
tests (Mann-Kendall and Spearman’s Rho) are applied to
detect trends at 10%, 5%, and 1% significance levels. Sub-hourly (6,
12, 18, and 30 minutes) annual maximum rainfall events have been
found to experience statistically significant upward trends at 10%
level of significance. However, sub-daily durations (1 hour, 3 and 12
hours) exhibit decreasing trends and no trends exists for longer
duration rainfall events (e.g. 24 and 72 hours). Some of the durations
(e.g. 6 minutes and 6 hours) show similar results (with upward
trends) for both the tests. For 12, 18, 60 minutes and 3 hours
durations both the tests show similar downward trends. This finding
has important implication for Tasmania in the design of urban
infrastructure where shorter duration rainfall events are more relevant
for smaller urban catchments such as parking lots, roof catchments
and smaller sub-divisions.
Abstract: Multiwall carbon nanotubes, prepared by chemical
vapor deposition, have an average diameter of 60-100 nm as shown
by High Resolution Transmittance Electron Microscope, HR-TEM.
The Multiwall carbon nanotubes (MWCNTs) were further
characterized using X-ray Diffraction and Raman Spectroscopy.
Mercury uptake capacity of MWCNTs was studied using batch
adsorption method at different concentration ranges up to 150 ppm.
Mercury concentration (before and after the treatment) was measured
using cold vapor atomic absorption spectroscopy. The effect of time,
concentration, pH and adsorbent dose were studied. MWCNT were
found to perform complete absorption in the sub-ppm concentrations
(parts per billion levels) while for high concentrations, the adsorption
efficiency was 92% at the optimum conditions; 0.1 g of the adsorbent
at 150 ppm mercury (II) solution. The adsorption of mercury on
MWCNTs was found to follow the Freundlich adsorption isotherm
and the pseudo-second order kinetic model.
Abstract: The phased-array ultrasound transducer types are
utilities for medical ultrasonography as well as optical imaging.
However, their discontinuity characteristic limits the applications due
to the artifacts contaminated into the reconstructed images. Because
of the effects of the ultrasound pressure field pattern to the echo
ultrasonic waves as well as the optical modulated signal, the side
lobes of the focused ultrasound beam induced by discontinuity of the
phased-array ultrasound transducer might the reason of the artifacts.
In this paper, a simple method in approach of numerical simulation
was used to investigate the limitation of discontinuity of the elements
in phased-array ultrasound transducer and their effects to the
ultrasound pressure field. Take into account the change of ultrasound
pressure field patterns in the conditions of variation of the pitches
between elements of the phased-array ultrasound transducer, the
appropriated parameters for phased-array ultrasound transducer
design were asserted quantitatively.
Abstract: In this paper two approaches to joint signal detection,
time of arrival (ToA) and angle of arrival (AoA) estimation in
multi-element antenna array are investigated. Two scenarios were
considered: first one, when the waveform of the useful signal
is known a priori and, second one, when the waveform of the
desired signal is unknown. For first scenario, the antenna array
signal processing based on multi-element matched filtering (MF)
with the following non-coherent detection scheme and maximum
likelihood (ML) parameter estimation blocks is exploited. For second
scenario, the signal processing based on the antenna array elements
covariance matrix estimation with the following eigenvector analysis
and ML parameter estimation blocks is applied. The performance
characteristics of both signal processing schemes are thoroughly
investigated and compared for different useful signals and noise
parameters.
Abstract: In this paper, the effect of WC-12Co particle
temperature in HVOF thermal spraying process on the coating
thickness has been studied. The statistical results show that the spray
distance and oxygen-to-fuel ratio are effective factors on particle
characterization and thickness of HVOF thermal spraying coatings.
Spray Watch diagnostic system, scanning electron microscopy
(SEM), X-ray diffraction and thickness measuring system were used
for this purpose.
Abstract: Ancillary services are support services which are
essential for humanizing and enhancing the reliability and security of
the electric power system. Reactive power ancillary service is one of
the important ancillary services in a restructured electricity market
which determines the cost of supplying ancillary services and finding
of how this cost would change with respect to operating decisions.
This paper presents a new formation that can be used to minimize the
Independent System Operator (ISO)’s total payment for reactive
power ancillary service. The modified power flow tracing algorithm
estimates the availability of reserve reactive power for ancillary
service. In order to find optimum reactive power dispatch,
Biogeography based optimization method (BPO) is proposed. Market
Reactive Clearing Price (MRCP) is then estimated and it encourages
generator companies (GENCOs) to participate in an ancillary service.
Finally, optimal weighting factor and real time utilization factor of
reactive power give the minimum ISO’s total payment. The
effectiveness of proposed design is verified using IEEE 30 bus
system.
Abstract: This paper presents a 4-DOF nonlinear model of a
cracked de Laval rotor-stator system derived based on Energy
Principles. The model has been used to simulate coupled torsionallateral
response of the faulty system with multiple parametric
excitations; rotor-stator-rub, a breathing transverse crack, eccentric
mass and an axial force. Nonlinearity of a “breathing” crack is
incorporated in the model using a simple hinge mechanism suitable
for a shallow crack. Response of the system while passing via its
critical speed with intermittent rotor-stator rub is analyzed. Effects of
eccentricity with phase and acceleration are investigated. Features of
crack, rub and eccentricity in vibration response are explored for
condition monitoring. The presence of a crack and rub are observable
in the power spectrum despite excitations by an axial force and rotor
unbalance. Obtained results are consistent with existing literature and
could be adopted into rotor condition monitoring strategies.
Abstract: reliability-based methodology for the assessment
and evaluation of reinforced concrete (R/C) structural elements of
concrete structures is presented herein. The results of the reliability
analysis and assessment for R/C structural elements were verified by
the results obtained through deterministic methods. The outcomes of
the reliability-based analysis were compared against currently
adopted safety limits that are incorporated in the reliability indices
β’s, according to international standards and codes. The methodology
is based on probabilistic analysis using reliability concepts and
statistics of the main random variables that are relevant to the subject
matter, and for which they are to be used in the performance-function
equation(s) associated with the structural elements under study.
These methodology techniques can result in reliability index β, which
is commonly known as the reliability index or reliability measure
value that can be utilized to assess and evaluate the safety, human
risk, and functionality of the structural component. Also, these
methods can result in revised partial safety factor values for certain
target reliability indices that can be used for the purpose of
redesigning the R/C elements of the building and in which they could
assist in considering some other remedial actions to improve the
safety and functionality of the member.
Abstract: Different strategies and tools are available at the oil
and gas industry for detecting and analyzing tension and possible
fractures in borehole walls. Most of these techniques are based on
manual observation of the captured borehole images. While this
strategy may be possible and convenient with small images and few
data, it may become difficult and suitable to errors when big
databases of images must be treated. While the patterns may differ
among the image area, depending on many characteristics (drilling
strategy, rock components, rock strength, etc.). In this work we
propose the inclusion of data-mining classification strategies in order
to create a knowledge database of the segmented curves. These
classifiers allow that, after some time using and manually pointing
parts of borehole images that correspond to tension regions and
breakout areas, the system will indicate and suggest automatically
new candidate regions, with higher accuracy. We suggest the use of
different classifiers methods, in order to achieve different knowledge
dataset configurations.
Abstract: Health analytics (HA) is used in healthcare systems
for effective decision making, management and planning of
healthcare and related activities. However, user resistances, unique
position of medical data content and structure (including
heterogeneous and unstructured data) and impromptu HA projects
have held up the progress in HA applications. Notably, the accuracy
of outcomes depends on the skills and the domain knowledge of the
data analyst working on the healthcare data. Success of HA depends
on having a sound process model, effective project management and
availability of supporting tools. Thus, to overcome these challenges
through an effective process model, we propose a HA process model
with features from rational unified process (RUP) model and agile
methodology.
Abstract: Brain functional networks based on resting-state EEG
data were compared between patients with mild Alzheimer’s disease
(mAD) and matched patients with amnestic subtype of mild cognitive
impairment (aMCI). We integrated the time–frequency cross mutual
information (TFCMI) method to estimate the EEG functional
connectivity between cortical regions and the network analysis based
on graph theory to further investigate the alterations of functional
networks in mAD compared with aMCI group. We aimed at
investigating the changes of network integrity, local clustering,
information processing efficiency, and fault tolerance in mAD brain
networks for different frequency bands based on several topological
properties, including degree, strength, clustering coefficient, shortest
path length, and efficiency. Results showed that the disruptions of
network integrity and reductions of network efficiency in mAD
characterized by lower degree, decreased clustering coefficient, higher
shortest path length, and reduced global and local efficiencies in the
delta, theta, beta2, and gamma bands were evident. The significant
changes in network organization can be used in assisting
discrimination of mAD from aMCI in clinical.
Abstract: Theoretical optimization of a copper-water negative
inclination heat pipe with internal composite wick structure had been
performed, regarding a new introduced parameter: the ratio between
the coarse mesh wraps and the fine mesh wraps of the composite
wick. Since in many cases, the design of a heat pipe matches specific
thermal requirements and physical limitations, this work
demonstrates the optimization of a 1m length, 8mm internal diameter
heat pipe without an adiabatic section, at a negative inclination angle
of -10º. The optimization is based on a new introduced parameter, LR:
the ratio between the coarse mesh wraps and the fine mesh wraps.
Abstract: This study is an attempt to raise the awareness of the
stakeholders and the authorities on the sensitivity of Algerian
secondary school teachers of English as a Foreign Language about
the students’ loss of English language skills learned during formal
schooling with effort and at expense and the supposed measures to
arrest that loss. Data was collected from secondary school teachers of
EFL and analyzed quantitatively using a questionnaire containing
open-ended and close-ended questions. The results advocate a
consensus about the need for actions to be adopted to make
assessment techniques outcome-oriented. Most of the participants
were in favor of including curricular activities involving
contextualized learning, problem-solving learning critical selfawareness,
self and peer-assisted learning, use of computers and
internet so as to make learners autonomous.