Abstract: The purpose of this paper is to perform a multidisciplinary design and analysis (MDA) of honeycomb panels used in the satellites structural design. All the analysis is based on clamped-free boundary conditions. In the present work, detailed finite element models for honeycomb panels are developed and analysed. Experimental tests were carried out on a honeycomb specimen of which the goal is to compare the previous modal analysis made by the finite element method as well as the existing equivalent approaches. The obtained results show a good agreement between the finite element analysis, equivalent and tests results; the difference in the first two frequencies is less than 4% and less than 10% for the third frequency. The results of the equivalent model presented in this analysis are obtained with a good accuracy. Moreover, investigations carried out in this research relate to the honeycomb plate modal analysis under several aspects including the structural geometrical variation by studying the various influences of the dimension parameters on the modal frequency, the variation of core and skin material of the honeycomb. The various results obtained in this paper are promising and show that the geometry parameters and the type of material have an effect on the value of the honeycomb plate modal frequency.
Abstract: Automatic segmentation of skin lesions is the first step
towards development of a computer-aided diagnosis of melanoma.
Although numerous segmentation methods have been developed,
few studies have focused on determining the most discriminative
and effective color space for melanoma application. This paper
proposes a novel automatic segmentation algorithm using color space
analysis and clustering-based histogram thresholding, which is able to
determine the optimal color channel for segmentation of skin lesions.
To demonstrate the validity of the algorithm, it is tested on a set of 30
high resolution dermoscopy images and a comprehensive evaluation
of the results is provided, where borders manually drawn by four
dermatologists, are compared to automated borders detected by the
proposed algorithm. The evaluation is carried out by applying three
previously used metrics of accuracy, sensitivity, and specificity and
a new metric of similarity. Through ROC analysis and ranking the
metrics, it is shown that the best results are obtained with the X and
XoYoR color channels which results in an accuracy of approximately
97%. The proposed method is also compared with two state-ofthe-
art skin lesion segmentation methods, which demonstrates the
effectiveness and superiority of the proposed segmentation method.
Abstract: A filter is used to remove undesirable frequency information from a dynamic signal. This paper shows that the Znotch filter filtering technique can be applied to remove the noise nuisance from a machining signal. In machining, the noise components were identified from the sound produced by the operation of machine components itself such as hydraulic system, motor, machine environment and etc. By correlating the noise components with the measured machining signal, the interested components of the measured machining signal which was less interfered by the noise, can be extracted. Thus, the filtered signal is more reliable to be analysed in terms of noise content compared to the unfiltered signal. Significantly, the I-kaz method i.e. comprises of three dimensional graphical representation and I-kaz coefficient, Z∞ could differentiate between the filtered and the unfiltered signal. The bigger space of scattering and the higher value of Z∞ demonstrated that the signal was highly interrupted by noise. This method can be utilised as a proactive tool in evaluating the noise content in a signal. The evaluation of noise content is very important as well as the elimination especially for machining operation fault diagnosis purpose. The Z-notch filtering technique was reliable in extracting noise component from the measured machining signal with high efficiency. Even though the measured signal was exposed to high noise disruption, the signal generated from the interaction between cutting tool and work piece still can be acquired. Therefore, the interruption of noise that could change the original signal feature and consequently can deteriorate the useful sensory information can be eliminated.
Abstract: Several models have been introduced so far for single
electron box, SEB, which all of them were restricted to DC response
and or low temperature limit. In this paper we introduce a new time
dependent, high temperature analytical model for SEB for the first
time. DC behavior of the introduced model will be verified against
SIMON software and its time behavior will be verified against a
newly published paper regarding step response of SEB.
Abstract: In this paper the design of maximally flat linear phase
finite impulse response (FIR) filters is considered. The problem is
handled with totally two different approaches. The first one is
completely deterministic numerical approach where the problem is
formulated as a Linear Complementarity Problem (LCP). The other
one is based on a combination of Markov Random Fields (MRF's)
approach with messy genetic algorithm (MGA). Markov Random
Fields (MRFs) are a class of probabilistic models that have been
applied for many years to the analysis of visual patterns or textures.
Our objective is to establish MRFs as an interesting approach to
modeling messy genetic algorithms. We establish a theoretical result
that every genetic algorithm problem can be characterized in terms of
a MRF model. This allows us to construct an explicit probabilistic
model of the MGA fitness function and introduce the Ising MGA.
Experimentations done with Ising MGA are less costly than those
done with standard MGA since much less computations are involved.
The least computations of all is for the LCP. Results of the LCP,
random search, random seeded search, MGA, and Ising MGA are
discussed.
Abstract: This paper presents a useful sub-pixel image
registration method using line segments and a sub-pixel edge detector.
In this approach, straight line segments are first extracted from gray
images at the pixel level before applying the sub-pixel edge detector.
Next, all sub-pixel line edges are mapped onto the orientation-distance
parameter space to solve for line correspondence between images.
Finally, the registration parameters with sub-pixel accuracy are
analytically solved via two linear least-square problems. The present
approach can be applied to various fields where fast registration with
sub-pixel accuracy is required. To illustrate, the present approach is
applied to the inspection of printed circuits on a flat panel. Numerical
example shows that the present approach is effective and accurate
when target images contain a sufficient number of line segments,
which is true in many industrial problems.
Abstract: In this paper, a methodology of a model based on
predicting the tool forces oblique machining are introduced by
adopting the orthogonal technique. The applied analytical calculation
is mostly based on Devries model and some parts of the methodology
are employed from Amareggo-Brown model. Model validation is
performed by comparing experimental data with the prediction results
on machining titanium alloy (Ti-6Al-4V) based on micro-cutting tool
perspective. Good agreements with the experiments are observed. A
detailed friction form that affected the tool forces also been examined
with reasonable results obtained.
Abstract: Shear-layer instabilities of a pulsed stack-issued
transverse jet were studied experimentally in a wind tunnel. Jet
pulsations were induced by means of acoustic excitation. Streak
pictures of the smoke-flow patterns illuminated by the laser-light sheet
in the median plane were recorded with a high-speed digital camera.
Instantaneous velocities of the shear-layer instabilities in the flow were
digitized by a hot-wire anemometer. By analyzing the streak pictures
of the smoke-flow visualization, three characteristic flow modes,
synchronized flapping jet, transition, and synchronized shear-layer
vortices, are identified in the shear layer of the pulsed stack-issued
transverse jet at various excitation Strouhal numbers. The shear-layer
instabilities of the pulsed stack-issued transverse jet are synchronized
by acoustic excitation except for transition mode. In transition flow
mode, the shear-layer vortices would exhibit a frequency that would be
twice as great as the acoustic excitation frequency.
Abstract: This paper is a survey of current component-based
software technologies and the description of promotion and
inhibition factors in CBSE. The features that software components
inherit are also discussed. Quality Assurance issues in componentbased
software are also catered to. The feat research on the quality
model of component based system starts with the study of what the
components are, CBSE, its development life cycle and the pro &
cons of CBSE. Various attributes are studied and compared keeping
in view the study of various existing models for general systems and
CBS. When illustrating the quality of a software component an apt
set of quality attributes for the description of the system (or
components) should be selected. Finally, the research issues that can
be extended are tabularized.
Abstract: Bluetooth is a personal wireless communication
technology and is being applied in many scenarios. It is an emerging
standard for short range, low cost, low power wireless access
technology. Current existing MAC (Medium Access Control)
scheduling schemes only provide best-effort service for all masterslave
connections. It is very challenging to provide QoS (Quality of
Service) support for different connections due to the feature of
Master Driven TDD (Time Division Duplex). However, there is no
solution available to support both delay and bandwidth guarantees
required by real time applications. This paper addresses the issue of
how to enhance QoS support in a Bluetooth piconet. The Bluetooth
specification proposes a Round Robin scheduler as possible solution
for scheduling the transmissions in a Bluetooth Piconet. We propose
an algorithm which will reduce the bandwidth waste and enhance the
efficiency of network. We define token counters to estimate traffic of
real-time slaves. To increase bandwidth utilization, a back-off
mechanism is then presented for best-effort slaves to decrease the
frequency of polling idle slaves. Simulation results demonstrate that
our scheme achieves better performance over the Round Robin
scheduling.
Abstract: In research on natural ventilation, and passive cooling
with forced convection, is essential to know how heat flows in a solid
object and the pattern of temperature distribution on their surfaces,
and eventually how air flows through and convects heat from the
surfaces of steel under roof. This paper presents some results from
running the computational fluid dynamic program (CFD) by
comparison between natural ventilation and forced convection within
roof attic that is received directly from solar radiation. The CFD
program for modeling air flow inside roof attic has been modified to
allow as two cases. First case, the analysis under natural ventilation,
is closed area in roof attic and second case, the analysis under forced
convection, is opened area in roof attic. These extend of all cases to
available predictions of variations such as temperature, pressure, and
mass flow rate distributions in each case within roof attic. The
comparison shows that this CFD program is an effective model for
predicting air flow of temperature and heat transfer coefficient
distribution within roof attic. The result shows that forced convection
can help to reduce heat transfer through roof attic and an around area
of steel core has temperature inner zone lower than natural
ventilation type. The different temperature on the steel core of roof
attic of two cases was 10-15 oK.
Abstract: The fluid mechanics principle is used extensively in
designing axial flow fans and their associated equipment. This paper presents a computational fluid dynamics (CFD) modeling of air flow
distribution from a radiator axial flow fan used in an acid pump truck Tier4 (APT T4) Repower. This axial flow fan augments the transfer
of heat from the engine mounted on the APT T4.
CFD analysis was performed for an area weighted average static pressure difference at the inlet and outlet of the fan. Pressure contours, velocity vectors, and path lines were plotted for detailing
the flow characteristics for different orientations of the fan blade. The results were then compared and verified against known theoretical observations and actual experimental data. This study
shows that a CFD simulation can be very useful for predicting and understanding the flow distribution from a radiator fan for further
research work.
Abstract: The objective of this paper is to analyze the
performance of a double-sided axial flux permanent magnet
brushless DC (AFPM BLDC) motor with two-phase winding.
To study the motor operation, a mathematical dynamic model
has been proposed for motor, which became the basis for
simulations that were performed using MATLAB/SIMULINK
software package. The results of simulations were presented
in form of the waveforms of selected quantities and the
electromechanical characteristics performed by the motor. The
calculation results show that the two-phase motor version
develops smooth torque and reaches high efficiency. The twophase
motor can be applied where more smooth torque is
required. Finally a study on the influence of switching angle
on motor performance shows that when advance switching
technique is used, the motor operates with the highest
efficiency.
Abstract: Water has always been a very precious resource.
However, many of us do not fully understand or appreciate water-s
value until there will be a shortage. We intended to analyze the water
consumption into the Spanish households to understand their
behavior according to the habitants of the house. In this research was
carried out a survey of users, asking for water consumption of their
households. The aim of this paper is get a reference value of
consumers in Spanish households to help to check their bill and
realize if their consumption is excessive, including some tips to
decrease it.
Abstract: Failure in mastery of motor skills proficiency during
childhood has been seen as a detrimental factor for children to be
physically active. Lack of motor skills proficiency tends to reduce
children’s competency and confidence level to participate in physical
activity. As a consequence of less participation in physical activity,
children will turn to be overweight and obese. It has been suggested
that children who master motor skill proficiency will be more
involved in physical activity thus preventing them from being
overweight. Obesity has become a serious childhood health issues
worldwide. Previous studies have found that children who were
overweight and obese were generally less active however these
studies focused on one gender. This study aims to compare motor
skill proficiency of underweight, normal-weight, overweight and
obese young boys as well as to determine the relationship between
motor skills proficiency and body composition. 112 boys aged
between 8 to 10 years old participated in this study. Participants were
assigned to four groups; underweight, normal-weight, overweight and
obese using BMI-age percentile chart for children. Bruininks-
Oseretsky Test Second Edition-Short Form was administered to
assess their motor skill proficiency. Meanwhile, body composition
was determined by the skinfold thickness measurement. Result
indicated that underweight and normal children were superior in
motor skills proficiency compared to overweight and obese children
(p < 0.05). A significant strong inverse correlation between motor
skills proficiency and body composition (r = -0.849) is noted. The
findings of this study could be explained by non-contributory mass
that carried by overweight and obese children leads to biomechanical
movement inefficiency which will become detrimental to motor skills
proficiency. It can be concluded that motor skills proficiency is
inversely correlated with body composition.
Abstract: Combined experimental and computational analysis of
hygrothermal performance of an interior thermal insulation system
applied on a brick wall is presented in the paper. In the experimental
part, the functionality of the insulation system is tested at simulated
difference climate conditions using a semi-scale device. The
measured temperature and relative humidity profiles are used for the
calibration of computer code HEMOT that is finally applied for a
long-term hygrothermal analysis of the investigated structure.
Abstract: Fabrication and efficiency enhancement of non-mercury, high efficiency and green field emission lamps using carbon nano-materials such as carbon nanotubes as cathode field emitters was studied. Phosphor was coated on the ITO glass or metal substrates as the anode. The luminescence efficiency enhancement was carried out by upgrading the uniform of the emitters, improving electron and thermal conductivity of the phosphor and the optimization of the design of different cathode/anode configurations. After evaluation of the aforementioned parameters, the luminescence efficiency of the field emission lamps was raised.
Abstract: An experiment was implemented in a filed in the south of Morocco to evaluate the effects of domestic treated wastewater use for irrigation of amaranth crop under semi-arid conditions. Three varieties (A0020, A0057 & A211) were tested and irrigated using domestic treated wastewater EC1 (0,92 dS/m) as control, EC3 (3dS/m) and EC6 (6dS/m) obtained by adding sea water. In term of growth, an increase of the EC level of applied irrigation water reduced significantly the plant-s height, leaf area, fresh and dry weight measured at vegetative, flowering and maturity stage for all varieties. Even with the application of the EC6, yields were relatively higher in comparison with the once obtained in normal cultivation conditions. A significant accumulation of nitrate, chloride and sodium in soil layers during the crop cycle was noted. The use of treated waste water for its irrigation is proved to be possible. The variety A211 had showed to be less sensitive to salinity stress and it could be more promising its introduction to study area.
Abstract: Falls are the primary cause of accidents in people over
the age of 65, and frequently lead to serious injuries. Since the early
detection of falls is an important step to alert and protect the aging
population, a variety of research on detecting falls was carried out
including the use of accelerators, gyroscopes and tilt sensors. In
exiting studies, falls were detected using an accelerometer with
errors. In this study, the proposed method for detecting falls was to
use two accelerometers to reject wrong falls detection. As falls are
accompanied by the acceleration of gravity and rotational motion, the
falls in this study were detected by using the z-axial acceleration
differences between two sites. The falls were detected by calculating
the difference between the analyses of accelerometers placed on two
different positions on the chest of the subject. The parameters of the
maximum difference of accelerations (diff_Z) and the integration of
accelerations in a defined region (Sum_diff_Z) were used to form the
fall detection algorithm. The falls and the activities of daily living
(ADL) could be distinguished by using the proposed parameters
without errors in spite of the impact and the change in the positions
of the accelerometers. By comparing each of the axial accelerations,
the directions of falls and the condition of the subject afterwards
could be determined.In this study, by using two accelerometers
without errors attached to two sites to detect falls, the usefulness of
the proposed fall detection algorithm parameters, diff_Z and
Sum_diff_Z, were confirmed.
Abstract: In a recent major industry-supported research and development study, a novel framework was developed and applied for assessment of reliability and quality performance levels in reallife power systems with practical large-scale sizes. The new assessment methodology is based on three metaphors (dimensions) representing the relationship between available generation capacities and required demand levels. The paper shares the results of the successfully completed stud and describes the implementation of the new methodology on practical zones in the Saudi electricity system.