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 this paper, a few chattering-free Sliding Mode Controllers (SMC) are proposed to stabilize an Active Magnetic Bearing (AMB) system with gyroscopic effect that is proportional to the rotor speed. The improved switching terms of the controller inherited from the saturation-type function and boundary layer control technique is shown to be able to achieve bounded and asymptotic stability, respectively, while the chattering effect in the input is attenuated. This is proven to be advantageous for AMB system since minimization of chattering results in optimized control effort. The performance of each controller is demonstrated via result of simulation in which the measurement of the total consumed energy and maximum control magnitude of each controller illustrates the effectiveness of the proposed controllers.
Abstract: The Platform Screen Doors improve Indoor Air Quality
(IAQ) in the subway station; however, and the air quality is degraded
in the subway tunnel. CO2 concentration and indoor particulate matter
value are high in the tunnel. The IAQ level in subway tunnel degrades
by increasing the train movements. Air-curtain installation reduces
dusts, particles and moving toxic smokes and permits traffic by
generating virtual wall. The ventilation systems of the subway tunnel
need improvements to have better air-quality. Numerical analyses
might be effective tools analyze the flowfield inside the air-curtain
installed subway tunnel. The ANSYS CFX software is used for steady
computations of the airflow inside the tunnel. The single-track subway
tunnel has the natural shaft, the mechanical shaft, and the PSDs
installed stations. The height and width of the tunnel are 6.0 m and 4.0
m respectively. The tunnel is 400 m long and the air-curtain is installed
at the top of the tunnel. The thickness and the width of the air-curtain
are 0.08 m and 4 m respectively. The velocity of the air-curtain
changes between 20 - 30 m/s. Three cases are analyzed depending on
the installing location of the air-curtain. The discharged-air through
the natural shafts increases as the velocity of the air-curtain increases
when the air-curtain is installed between the mechanical and the
natural shafts. The pollutant-air is exhausted by the mechanical and the
natural shafts and remained air is pushed toward tunnel end. The
discharged-air through the natural shaft is low when the air-curtain
installed before the natural shaft. The mass flow rate decreases in the
tunnel after the mechanical shaft as the air-curtain velocity increases.
The computational results of the air-curtain installed tunnel become
basis for the optimum design study. The air-curtain installing location
is chosen between the mechanical and the natural shafts. The velocity
of the air-curtain is fixed as 25 m/s. The thickness and the blowing
angles of the air-curtain are the design variables for the optimum
design study. The object function of the design optimization is
maximizing the discharged air through the natural shaft.
Abstract: Cement stabilization has been widely used for
improving the strength and stiffness of soft clayey soils. Cement
treated soil specimens used to investigate the stress-strain behaviour in
the laboratory study are usually cured for 7 days. This paper examines
the effects of curing time on the strength and stress strain behaviour of
cement treated marine clay under triaxial loading condition.
Laboratory-prepared cement treated Singapore marine clay with
different mix proportion S-C-W (soil solid-cement solid-water) and
curing time (7 days to 180 days) was investigated through conducting
unconfined compressive strength test and triaxial test. The results
show that the curing time has a significant effect on the unconfined
compressive strength u q , isotropic compression behaviour and stress
strain behaviour. Although the primary yield loci of the cement treated
soil specimens with the same mix proportion expand with curing time,
they are very narrowly banded and have nearly the same shape after
being normalized by isotropic compression primary stress '
py p . The
isotropic compression primary yield stress '
py p was shown to be
linearly related to unconfined compressive strength u q for specimens
with different curing time and mix proportion. The effect of curing
time on the hardening behaviour will diminish with consolidation
stress higher than isotropic compression primary yield stress but its
damping rate is dependent on the cement content.
Abstract: Deep cold rolling (DCR) and low plasticity burnishing (LPB) process are cold working processes, which easily produce a smooth and work-hardened surface by plastic deformation of surface irregularities. The present study focuses on the surface roughness and surface hardness aspects of AISI 4140 work material, using fractional factorial design of experiments. The assessment of the surface integrity aspects on work material was done, in order to identify the predominant factors amongst the selected parameters. They were then categorized in order of significance followed by setting the levels of the factors for minimizing surface roughness and/or maximizing surface hardness. In the present work, the influence of main process parameters (force, feed rate, number of tool passes/overruns, initial roughness of the work piece, ball material, ball diameter and lubricant used) on the surface roughness and the hardness of AISI 4140 steel were studied for both LPB and DCR process and the results are compared. It was observed that by using LPB process surface hardness has been improved by 167% and in DCR process surface hardness has been improved by 442%. It was also found that the force, ball diameter, number of tool passes and initial roughness of the workpiece are the most pronounced parameters, which has a significant effect on the work piece-s surface during deep cold rolling and low plasticity burnishing process.
Abstract: Sedimentation in reservoirs and the corresponding
loss of storage capacity is one of the most serious problems in dam
engineering. Pressurized flushing, a way to remove sediments from the reservoir, is flushing under a pressurized flow condition and
nearly constant water level. Pressurized flushing has only local
effects around the outlet. Sediment in the vicinity of the outlet openings is scoured and a funnel shaped crater is created. In this study, the temporal development of flushing cone under various
hydraulic conditions was studied experimentally. Time variations of
parameters such as maximum length and width of flushing and also
depth of scouring cone was measured. Results indicated that an
increase in flow velocity (and consequently in Froude number)
established new hydraulically conditions for flushing mechanism and
so a sudden growth was observed in the amount of sediment released
and also scouring dimenssions. In addition, a set of nondimensional
relationships were identified for temporal variations of flushing scour
dimenssions, which can eventuallt be used to estimate the development of flushing cone.
Abstract: In order to calculate the flexural strength of
normal-strength concrete (NSC) beams, the nonlinear actual concrete
stress distribution within the compression zone is normally replaced
by an equivalent rectangular stress block, with two coefficients of α
and β to regulate the intensity and depth of the equivalent stress
respectively. For NSC beams design, α and β are usually assumed
constant as 0.85 and 0.80 in reinforced concrete (RC) codes. From an
earlier investigation of the authors, α is not a constant but significantly
affected by flexural strain gradient, and increases with the increasing
of strain gradient till a maximum value. It indicates that larger
concrete stress can be developed in flexure than that stipulated by
design codes. As an extension and application of the authors- previous
study, the modified equivalent concrete stress block is used here to
produce a series of design charts showing the maximum design limits
of flexural strength and ductility of singly- and doubly- NSC beams,
through which both strength and ductility design limits are improved
by taking into account strain gradient effect.
Abstract: In the traditional theory of non-uniform torsion the
axial displacement field is expressed as the product of the unit twist
angle and the warping function. The first one, variable along the
beam axis, is obtained by a global congruence condition; the second
one, instead, defined over the cross-section, is determined by solving
a Neumann problem associated to the Laplace equation, as well as for
the uniform torsion problem.
So, as in the classical theory the warping function doesn-t punctually
satisfy the first indefinite equilibrium equation, the principal aim of
this work is to develop a new theory for non-uniform torsion of
beams with axial symmetric cross-section, fully restrained on both
ends and loaded by a constant torque, that permits to punctually
satisfy the previous equation, by means of a trigonometric expansion
of the axial displacement and unit twist angle functions.
Furthermore, as the classical theory is generally applied with good
results to the global and local analysis of ship structures, two beams
having the first one an open profile, the second one a closed section,
have been analyzed, in order to compare the two theories.
Abstract: We demonstrate through a sample application, Ebanking,
that the Web Service Modelling Language Ontology component
can be used as a very powerful object-oriented database design
language with logic capabilities. Its conceptual syntax allows the
definition of class hierarchies, and logic syntax allows the definition
of constraints in the database. Relations, which are available for
modelling relations of three or more concepts, can be connected to
logical expressions, allowing the implicit specification of database
content. Using a reasoning tool, logic queries can also be made
against the database in simulation mode.
Abstract: A full six degrees of freedom (6-DOF) flight dynamics
model is proposed for the accurate prediction of short and long-range
trajectories of high spin and fin-stabilized projectiles via atmospheric
flight to final impact point. The projectiles is assumed to be both rigid
(non-flexible), and rotationally symmetric about its spin axis launched
at low and high pitch angles. The mathematical model is based on the
full equations of motion set up in the no-roll body reference frame and
is integrated numerically from given initial conditions at the firing
site. The projectiles maneuvering motion depends on the most
significant force and moment variations, in addition to wind and
gravity. The computational flight analysis takes into consideration the
Mach number and total angle of attack effects by means of the
variable aerodynamic coefficients. For the purposes of the present
work, linear interpolation has been applied from the tabulated database
of McCoy-s book. The developed computational method gives
satisfactory agreement with published data of verified experiments and
computational codes on atmospheric projectile trajectory analysis for
various initial firing flight conditions.
Abstract: In the planning point of view, it is essential to have
mode choice, due to the massive amount of incurred in transportation
systems. The intercity travellers in Libya have distinct features, as
against travellers from other countries, which includes cultural and
socioeconomic factors. Consequently, the goal of this study is to
recognize the behavior of intercity travel using disaggregate models,
for projecting the demand of nation-level intercity travel in Libya.
Multinomial Logit Model for all the intercity trips has been
formulated to examine the national-level intercity transportation in
Libya. The Multinomial logit model was calibrated using nationwide
revealed preferences (RP) and stated preferences (SP) survey. The
model was developed for deference purpose of intercity trips (work,
social and recreational). The variables of the model have been
predicted based on maximum likelihood method. The data needed for
model development were obtained from all major intercity corridors
in Libya. The final sample size consisted of 1300 interviews. About
two-thirds of these data were used for model calibration, and the
remaining parts were used for model validation. This study, which is
the first of its kind in Libya, investigates the intercity traveler’s
mode-choice behavior. The intercity travel mode-choice model was
successfully calibrated and validated. The outcomes indicate that, the
overall model is effective and yields higher precision of estimation.
The proposed model is beneficial, due to the fact that, it is receptive
to a lot of variables, and can be employed to determine the impact of
modifications in the numerous characteristics on the need for various
travel modes. Estimations of the model might also be of valuable to
planners, who can estimate possibilities for various modes and
determine the impact of unique policy modifications on the need for
intercity travel.
Abstract: In this paper, we derive some algebraic identities on
right and left neighbors R(F) and L(F) of an indefinite binary
quadratic form F = F(x, y) = ax2 + bxy + cy2 of discriminant
Δ = b2 -4ac. We prove that the proper cycle of F can be given by
using its consecutive left neighbors. Also we construct a connection
between right and left neighbors of F.
Abstract: Radio Frequency Identification (RFID) initially introduced
during WW-II, has revolutionized the world with its numerous
benefits and plethora of implementations in diverse areas ranging
from manufacturing to agriculture to healthcare to hotel management.
This work reviews the current research in this area with emphasis
on applications for supply chain management and to develop a
taxonomic framework to classify literature which will enable swift
and easy content analysis and also help identify areas for future
research.
Abstract: ECG analysis method was developed using ROC
analysis of PVC detecting algorithm. ECG signal of MIT-BIH
arrhythmia database was analyzed by MATLAB. First of all, the
baseline was removed by median filter to preprocess the ECG signal.
R peaks were detected for ECG analysis method, and normal VCG
was extracted for VCG analysis method. Four PVC detecting
algorithm was analyzed by ROC curve, which parameters are
maximum amplitude of QRS complex, width of QRS complex, r-r
interval and geometric mean of VCG. To set cut-off value of
parameters, ROC curve was estimated by true-positive rate
(sensitivity) and false-positive rate. sensitivity and false negative rate
(specificity) of ROC curve calculated, and ECG was analyzed using
cut-off value which was estimated from ROC curve. As a result, PVC
detecting algorithm of VCG geometric mean have high availability,
and PVC could be detected more accurately with amplitude and width
of QRS complex.
Abstract: To satisfy the need of outfield tests of star sensors, a
method is put forward to construct the reference attitude benchmark.
Firstly, its basic principle is introduced; Then, all the separate
conversion matrixes are deduced, which include: the conversion
matrix responsible for the transformation from the Earth Centered
Inertial frame i to the Earth-centered Earth-fixed frame w according to
the time of an atomic clock, the conversion matrix from frame w to the
geographic frame t, and the matrix from frame t to the platform frame
p, so the attitude matrix of the benchmark platform relative to the
frame i can be obtained using all the three matrixes as the
multiplicative factors; Next, the attitude matrix of the star sensor
relative to frame i is got when the mounting matrix from frame p to the
star sensor frame s is calibrated, and the reference attitude angles for
star sensor outfield tests can be calculated from the transformation
from frame i to frame s; Finally, the computer program is finished to
solve the reference attitudes, and the error curves are drawn about the
three axis attitude angles whose absolute maximum error is just 0.25ÔÇ│.
The analysis on each loop and the final simulating results manifest that
the method by precise timing to acquire the absolute reference attitude
is feasible for star sensor outfield tests.
Abstract: The photoluminescence (PL) at 1.55 μm from
semiconducting β-FeSi2 has attracted a noticeable interest for
silicon-based optoelectronic applications. Moreover, its high optical
absorption coefficient (higher than 105 cm-1 above 1.0 eV) allows this
semiconducting material to be used as photovoltanics devices.
A clear PL spectrum for β-FeSi2 was observed by Cu or Au coating
on Si(001). High-crystal-quality β-FeSi2 with a low-level nonradiative
center was formed on a Cu- or Au- reated Si layer. This method of
deposition can be applied to other materials requiring high crystal
quality.
Abstract: In this paper an average number of re-handlings
analysis is proposed to solve the problem of finding bays
configuration in small container terminal in Gliwice, Poland.
Rehandlings in this terminal can be performed only by reachstackers.
The goal of the heuristic is to plan the reachstacter moves in the
terminal, assuming that the target containers are reached and the
number of re-handings is minimized. The real situation requires also
to take into account the model of the problem environment
uncertainty caused by the fact that many containers are not delivered
to the terminal on time, or can not be sent on scheduled time. To
enable this, the heuristic uses some assumptions to simplify problem
analysis.
Abstract: The principal objective of a water treatment plant is to
produce water that satisfies a set of drinking water quality standards
at a reasonable price to the consumers. The gravel-bed flocculator
provide a simple and inexpensive design for flocculation in small
water treatment plants (less than 5000 m3/day capacity). The packed
bed of gravel provides ideal conditions for the formation of compact
settleable flocs because of continuous recontact provided by the
sinuous flow of water through the interstices formed by the gravel.
The field data which were obtained from the operation of the
water supply treatment unit cover the physical, chemical and
biological water qualities of the raw and settled water as obtained by
the operation of the treatment unit. The experiments were carried out
with the aim of assessing the efficiency of the gravel filter in
removing the turbidity, pathogenic bacteria, from the raw water. The
water treatment plant, which was constructed for the treatment of
river water, was in principle a rapid sand filter.
The results show that the average value of the turbidity level of
the settled water was 4.83 NTU with a standard deviation of turbidity
2.893 NTU. This indicated that the removal efficiency of the
sedimentation tank (gravel filter) was about 67.8 %. for pH values
fluctuated between 7.75 and 8.15, indicating the alkaline nature of
the raw water of the river Shatt Al-Hilla, as expected. Raw water pH
is depressed slightly following alum coagulation. The pH of the
settled water ranged from 7.75 to a maximum of 8.05.
The bacteriological tests which were carried out on the water
samples were: total coliform test, E-coli test, and the plate count test.
In each test the procedure used was as outlined in the Standard
Methods for the Examination of Water and Wastewater (APHA,
AWWA, and WPCF, 1985). The gravel filter exhibit a low
performance in removing bacterial load. The percentage bacterial
removal, which is maximum for total plate count (19%) and
minimum for total coliform (16.82%).
Abstract: The recent developments in computing and
communication technology permit to users to access multimedia
documents with variety of devices (PCs, PDAs, mobile phones...)
having heterogeneous capabilities. This diversification of supports
has trained the need to adapt multimedia documents according to
their execution contexts. A semantic framework for multimedia
document adaptation based on the conceptual neighborhood graphs
was proposed. In this framework, adapting consists on finding
another specification that satisfies the target constraints and which is
as close as possible from the initial document. In this paper, we
propose a new way of building the conceptual neighborhood graphs
to best preserve the proximity between the adapted and the original
documents and to deal with more elaborated relations models by
integrating the relations relaxation graphs that permit to handle the
delays and the distances defined within the relations.
Abstract: Stick models are widely used in studying the
behaviour of straight as well as skew bridges and viaducts subjected
to earthquakes while carrying out preliminary studies. The
application of such models to highly curved bridges continues to
pose challenging problems. A viaduct proposed in the foothills of the
Himalayas in Northern India is chosen for the study. It is having 8
simply supported spans @ 30 m c/c. It is doubly curved in horizontal
plane with 20 m radius. It is inclined in vertical plane as well. The
superstructure consists of a box section. Three models have been
used: a conventional stick model, an improved stick model and a 3D
finite element model. The improved stick model is employed by
making use of body constraints in order to study its capabilities. The
first 8 frequencies are about 9.71% away in the latter two models.
Later the difference increases to 80% in 50th mode. The viaduct was
subjected to all three components of the El Centro earthquake of May
1940. The numerical integration was carried out using the Hilber-
Hughes-Taylor method as implemented in SAP2000. Axial forces
and moments in the bridge piers as well as lateral displacements at
the bearing levels are compared for the three models. The maximum
difference in the axial forces and bending moments and
displacements vary by 25% between the improved and finite element
model. Whereas, the maximum difference in the axial forces,
moments, and displacements in various sections vary by 35%
between the improved stick model and equivalent straight stick
model. The difference for torsional moment was as high as 75%. It is
concluded that the stick model with body constraints to model the
bearings and expansion joints is not desirable in very sharp S curved
viaducts even for preliminary analysis. This model can be used only
to determine first 10 frequency and mode shapes but not for member
forces. A 3D finite element analysis must be carried out for
meaningful results.