Abstract: Recently, the improvements in processing performance
of a computer and in high speed communication of an optical fiber
have been achieved, so that the amount of data which are processed
by a computer and flowed on a network has been increasing greatly.
However, in a client-server system, since the server receives and
processes the amount of data from the clients through the network, a
load on the server is increasing. Thus, there are needed to introduce
a server with high processing ability and to have a line with high
bandwidth. In this paper, concerning to P2P networks to resolve the
load on a specific server, a criterion called an Indexed-Priority Metric
is proposed and its performance is evaluated. The proposed metric is
to allocate some files to each node. As a result, the load on a specific
server can distribute them to each node equally well. A P2P file
sharing system using the proposed metric is implemented. Simulation
results show that the proposed metric can make it distribute files on
the specific server.
Abstract: Efficient utilization of existing water is a pressing
need for Pakistan. Due to rising population, reduction in present
storage capacity and poor delivery efficiency of 30 to 40% from
canal. A study to evaluate an irrigation system in the cotton-wheat
zone of Pakistan, after the watercourse lining was conducted. The
study is made on the basis of cropping pattern and salinity to evaluate
the system. This study employed an index-based approach of using
Geographic information system with field data. The satellite images
of different years were use to examine the effective area. Several
combinations of the ratio of signals received in different spectral
bands were used for development of this index. Near Infrared and
Thermal IR spectral bands proved to be most effective as this
combination helped easy detection of salt affected area and cropping
pattern of the study area. Result showed that 9.97% area under
salinity in 1992, 9.17% in 2000 and it left 2.29% in year 2005.
Similarly in 1992, 45% area is under vegetation it improves to 56%
and 65% in 2000 and 2005 respectively. On the basis of these results
evaluation is done 30% performance is increase after the watercourse
improvement.
Abstract: A thin coating of hexamethyldisiloxane and subsequent O2-plasma treatment was performed on mirror-polished titanium in order to regulate the wide range of wettability including 106 and almost 0 degrees of contact angles. The adsorption behavior of
fibronectin and albumin in both individual and competitive mode,
and initial attachment of fibroblasts and osteoblasts were investigated.
Individually, fibronectin adsorption showed a biphasic inclination, whereas albumin showed greater adsorption to hydrophobic surfaces.
In competitive mode, in solution containing both fibronectin and albumin, fibronectin showed greater adsorption on hydrophilic
surfaces, whereas Alb predominantly adsorbed on hydrophobic
surfaces. Initial attachment of both cells increased with increase in
surface wettability, in particular, on super-hydrophilic surface, which
correlated well with fibronectin adsorption in competitive mode.
These results suggest that a cold plasma-surface modification enabled
to regulate the surface wettability, and fibronectin adsorption may be
responsible for increasing cell adhesion on hydrophilic surfaces in a
body fluid
Abstract: Localization is one of the critical issues in the field of
robot navigation. With an accurate estimate of the robot pose, robots will be capable of navigating in the environment autonomously and efficiently. In this paper, a hybrid Distributed Vision System (DVS)
for robot localization is presented. The presented approach integrates
odometry data from robot and images captured from overhead cameras
installed in the environment to help reduce possibilities of fail
localization due to effects of illumination, encoder accumulated errors,
and low quality range data. An odometry-based motion model is applied to predict robot poses, and robot images captured by overhead
cameras are then used to update pose estimates with HSV histogram-based measurement model. Experiment results show the
presented approach could localize robots in a global world coordinate system with localization errors within 100mm.
Abstract: Transportation is of great importance in the current
life of human beings. The transportation system plays many roles,
from economical development to after-catastrophe aids such as
rescue operation in the first hours and days after an earthquake. In
after earthquakes response phase, transportation system acts as a
basis for ground operations including rescue and relief operation,
food providing for victims and etc. It is obvious that partial or
complete obstruction of this system results in the stop of these
operations. Bridges are one of the most important elements of
transportation network. Failure of a bridge, in the most optimistic
case, cuts the relation between two regions and in more developed
countries, cuts the relation of numerous regions. In this paper, to
evaluate the vulnerability and estimate the damage level of Tehran
bridges, HAZUS method, developed by Federal Emergency
Management Agency (FEMA) with the aid of National Institute of
Building Science (NIBS), is used for the first time in Iran. In this
method, to evaluate the collapse probability, fragility curves are
used. Iran is located on seismic belt and thus, it is vulnerable to
earthquakes. Thus, the study of the probability of bridge collapses, as
an important part of transportation system, during earthquakes is of
great importance. The purpose of this study is to provide fragility
curves for Gisha Bridge, one of the longest steel bridges in Tehran,
as an important lifeline element. Besides, the damage probability for
this bridge during a specific earthquake, introduced as scenario
earthquakes, is calculated. The fragility curves show that for the
considered scenario, the probability of occurrence of complete
collapse for the bridge is 8.6%.
Abstract: The knowledge of the nature of loading is very
important in order to hold account on the total behavior such as
vibration, shock, fatigue, etc. Fatigue present 90% of failure when
loadings fatigues are very complex. In this paper a study of double
through crack at hole for plate subjected to fatigue loading is
presented. Various modes loading are studied where the applied load
is the same one. The fatigue life is given where the effect of stress
ratio is highlighted. This work is conducted on aluminum alloy 2024
T351 used for much aerospace and aeronautics applications. The
fatigue crack growth behavior with constant amplitude is studied
using the AFGROW code when Forman model is applied. The
fatigue crack growth rate and fatigue life for different loading modes
are compared with variation of others geometrical parameter such as
thickness and dimensions of notch hole.
Abstract: In this paper, we consider a designed and
implemented phase-cutting dimmer. In fact, the dimmer is closed
loop and a microcontroller calculates and then regulates the firing
delay angles of each channel. Depending on the firing angle, the
harmonic distortion in the input current will not comply with
international standards, such as IEC 61000-3-2 (class C equipments).
For solving this problem, eight harmonic compensators have been
added to the dimmer. So, the proposed dimmer has a little harmonic
distortion in the input current whereas conventional phase-cutting
dimmers are not so. Sensitivity and removed THD of the proposed
dimmer will be presented.
Abstract: Fatigue tests of specimen-s with numerous holes are
presented. The tests were made up till fatigue cracks have been
created on both sides of the hole. Their extension was stopping with
pressed plastic deformation at the mouth of the detected crack. It is
shown that the moments of occurrence of cracks on holes are
stochastically dependent. This dependence has positive and negative
correlation relations. Shown that the positive correlation is formed
across of the applied force, while negative one – along it. The
negative relationship extends over a greater distance. The
mathematical model of dependence area formation is represented as
well as the estimating of model parameters. The positive correlation
of fatigue cracks origination can be considered as an extension of one
main crack. With negative correlation the first crack locates the place
of its origin, leading to the appearance of multiple cracks; do not
merge with each other.
Abstract: Sensory input plays an important role to human
posture control system to initiate strategy in order to counterpart any
unbalance condition and thus, prevent fall. In previous study, joint
stiffness was observed able to describe certain issues regarding to
movement performance. But, correlation between balance ability and
joint stiffness is still remains unknown. In this study, joint stiffening
strategy at ankle and hip were observed under different sensory
manipulations and its correlation with conventional clinical test
(Functional Reach Test) for balance ability was investigated. In order
to create unstable condition, two different surface perturbations (tilt
up-tilt (TT) down and forward-backward (FB)) at four different
frequencies (0.2, 0.4, 0.6 and 0.8 Hz) were introduced. Furthermore,
four different sensory manipulation conditions (include vision and
vestibular system) were applied to the subject and they were asked to
maintain their position as possible. The results suggested that joint
stiffness were high during difficult balance situation. Less balance
people generated high average joint stiffness compared to balance
people. Besides, adaptation of posture control system under repetitive
external perturbation also suggested less during sensory limited
condition. Overall, analysis of joint stiffening response possible to
predict unbalance situation faced by human
Abstract: The voltage/current characteristics and the effect of
NO2 gas on the electrical conductivity of a PbPc gas sensor array is
investigated. The gas sensor is manufactured using vacuum
deposition of gold electrodes on sapphire substrate with the leadphathalocyanine
vacuum sublimed on the top of the gold electrodes.
Two versions of the PbPc gas sensor array are investigated. The
tested types differ in the gap sizes between the deposited gold
electrodes. The sensors are tested at different temperatures to account
for conductivity changes as the molecular adsorption/desorption rate
is affected by heat. The obtained results found to be encouraging as
the sensors shoed stability and sensitivity towards low concentration
of applied NO2 gas.
Abstract: All the available algorithms for blind estimation namely constant modulus algorithm (CMA), Decision-Directed Algorithm (DDA/DFE) suffer from the problem of convergence to local minima. Also, if the channel drifts considerably, any DDA looses track of the channel. So, their usage is limited in varying channel conditions. The primary limitation in such cases is the requirement of certain overhead bits in the transmit framework which leads to wasteful use of the bandwidth. Also such arrangements fail to use channel state information (CSI) which is an important aid in improving the quality of reception. In this work, the main objective is to reduce the overhead imposed by the pilot symbols, which in effect reduces the system throughput. Also we formulate an arrangement based on certain dynamic Artificial Neural Network (ANN) topologies which not only contributes towards the lowering of the overhead but also facilitates the use of the CSI. A 2×2 Multiple Input Multiple Output (MIMO) system is simulated and the performance variation with different channel estimation schemes are evaluated. A new semi blind approach based on dynamic ANN is proposed for channel tracking in varying channel conditions and the performance is compared with perfectly known CSI and least square (LS) based estimation.
Abstract: Risk response planning is of importance for software project risk management (SPRM). In CMMI, risk management was in the third capability maturity level, which provides a framework for software project risk identification, assessment, risk planning, risk control. However, the CMMI-based SPRM currently lacks quantitative supporting tools, especially during the process of implementing software project risk planning. In this paper, an economic optimization model for selecting risk reduction actions in the phase of software project risk response planning is presented. Furthermore, an example taken from a Chinese software industry is illustrated to verify the application of this method. The research provides a risk decision method for project risk managers that can be used in the implementation of CMMI-based SPRM.
Abstract: Discharges in hydrogen, ignited by wire explosion, with current amplitude up to 1.5 MA were investigated. Channel diameter oscillations were observed on the photostreaks. Voltage and current curves correlated with the photostreaks. At initial gas pressure of 5-35 MPa the oscillation period was proportional to square root of atomic number of the initiating wire material. These oscillations were associated with aligned magnetic and gas-kinetic pressures. At initial pressure of 80-160 MPa acoustic pressure fluctuations on the discharge chamber wall were increased up to 150 MPa and there were the growth of voltage fluctuations on the discharge gap up to 3 kV simultaneously with it. In some experiments it was observed abrupt increase in the oscillation amplitude, which can be caused by the resonance of the acoustic oscillations in discharge chamber volume and the oscillations connected with alignment of the gaskinetic pressure and the magnetic pressure, as far as frequencies of these oscillations are close to each other in accordance with the estimates and the experimental data. Resonance of different type oscillations can produce energy density increasing in the discharge channel. Thus, the appropriate initial conditions in the experiment allow to increase the energy density in the discharge channel
Abstract: In this work, Experimental tie-line results and
solubility (binodal) curves were obtained for the ternary systems
(water + acetic acid + methyl isobutyl ketone (MIBK)), (water +
lactic acid+ methyl isobutyl ketone) at T = 294.15K and atmospheric
pressure. The consistency of the values of the experimental tie-lines
was determined through the Othmer-Tobias and Hands correlations.
For the extraction effectiveness of solvents, the distribution and
selectivity curves were plotted. In addition, these experimental tieline
data were also correlated with NRTL model. The interaction
parameters for the NRTL model were retrieved from the obtained
experimental results by means of a combination of the homotopy
method and the genetic algorithms.
Abstract: Designing a simulated system and training it to optimize its tasks in simulated environment helps the designers to avoid problems that may appear when designing the system directly in real world. These problems are: time consuming, high cost, high errors percentage and low efficiency and accuracy of the system. The proposed system will investigate and improve the efficiency and accuracy of a simulated robot to choose correct behavior to perform its task. In this paper, machine learning, which uses genetic algorithm, is adopted. This type of machine learning is called genetic-based machine learning in which a distributed classifier system is used to improve the efficiency and accuracy of the robot. Consequently, it helps the robot to achieve optimal action.
Abstract: The limit load carrying capacity of functionally
graded materials (FGM) circular plates subjected to an arbitrary
rotationally symmetric loading has been computed. It is provided that
the plate material behaves rigid perfectly plastic and obeys either the
Square or the Tresca yield criterion. To this end the upper and lower
bound principles of limit analysis are employed to determine the
exact value for the limiting load. The correctness of the result are
verified and finally limiting loads for two examples namely; through
radius and through thickness FGM circular plates with simply
supported edges are calculated, respectively and moreover, the values
of critical loading factor are determined.
Abstract: Permanent magnet synchronous machines are known
as a good candidate for hybrid electric vehicles due to their unique
merits. However they have two major drawbacks i.e. high cost and
small speed range. In this paper an optimal design of a permanent
magnet machine is presented. A reduction of permanent magnet
material for a constant torque and an extension in speed and torque
ranges are chosen as the optimization aims. For this purpose the
analytical model of the permanent magnet synchronous machine is
derived and the appropriate design algorithm is devised. The genetic
algorithm is then employed to optimize some machine specifications.
Finally the finite element method is used to validate the designed
machine.
Abstract: The paper discusses a 3D numerical solution of the inverse boundary problem for a continuous casting process of alloy. The main goal of the analysis presented within the paper was to estimate heat fluxes along the external surface of the ingot. The verified information on these fluxes was crucial for a good design of a mould, effective cooling system and generally the whole caster. In the study an enthalpy-porosity technique implemented in Fluent package was used for modeling the solidification process. In this method, the phase change interface was determined on the basis of the liquid fraction approach. In inverse procedure the sensitivity analysis was applied for retrieving boundary conditions. A comparison of the measured and retrieved values showed a high accuracy of the computations. Additionally, the influence of the accuracy of measurements on the estimated heat fluxes was also investigated.
Abstract: In this paper, the data correction algorithm is suggested
when the environmental air temperature varies. To correct the infrared
data in this paper, the initial temperature or the initial infrared image
data is used so that a target source system may not be necessary. The
temperature data obtained from infrared detector show nonlinear
property depending on the surface temperature. In order to handle this
nonlinear property, Taylor series approach is adopted. It is shown that
the proposed algorithm can reduce the influence of environmental
temperature on the components in the board. The main advantage of
this algorithm is to use only the initial temperature of the components
on the board rather than using other reference device such as black
body sources in order to get reference temperatures.
Abstract: The phase diagrams and compositions of coexisting
phases have been determined for aqueous two-phase systems
containing poly(propylene glycol) with average molecular weight of
425 and sodium citrate at various pH of 3.93, 4.44, 4.6, 4.97, 5.1,
8.22. The effect of pH on the salting-out effect of poly (propylene
glycol) by sodium citrate has been studied. It was found that, an
increasing in pH caused the expansion of two-phase region.
Increasing pH also increases the concentration of PPG in the PPGrich
phase, while the salt-rich phase will be somewhat mole diluted.