Abstract: Web usage mining has become a popular research
area, as a huge amount of data is available online. These data can be
used for several purposes, such as web personalization, web structure
enhancement, web navigation prediction etc. However, the raw log
files are not directly usable; they have to be preprocessed in order to
transform them into a suitable format for different data mining tasks.
One of the key issues in the preprocessing phase is to identify web
users. Identifying users based on web log files is not a
straightforward problem, thus various methods have been developed.
There are several difficulties that have to be overcome, such as client
side caching, changing and shared IP addresses and so on. This paper
presents three different methods for identifying web users. Two of
them are the most commonly used methods in web log mining
systems, whereas the third on is our novel approach that uses a
complex cookie-based method to identify web users. Furthermore we
also take steps towards identifying the individuals behind the
impersonal web users. To demonstrate the efficiency of the new
method we developed an implementation called Web Activity
Tracking (WAT) system that aims at a more precise distinction of
web users based on log data. We present some statistical analysis
created by the WAT on real data about the behavior of the Hungarian
web users and a comprehensive analysis and comparison of the three
methods
Abstract: Environment-assisted cracking (EAC) is one of the most serious causes of structural failure over a broad range of industrial applications including offshore structures. In EAC condition there is not a definite relation such as Paris equation in Linear Elastic Fracture Mechanics (LEFM). According to studying and searching a lot what the researchers said either a material has contact with hydrogen or any other corrosive environment, phenomenon of electrical and chemical reactions of material with its environment will be happened. In the literature, there are many different works to consider fatigue crack growing and solve it but they are experimental works. Thus, in this paper, authors have an aim to evaluate mathematically the pervious works in LEFM. Obviously, if an environment is more sour and corrosive, the changes of stress intensity factor is more and the calculation of stress intensity factor is difficult. A mathematical relation to deal with the stress intensity factor during the diffusion of sour environment especially hydrogen in a marine pipeline is presented. By using this relation having and some experimental relation an analytical formulation will be presented which enables the fatigue crack growth and critical crack length under cyclic loading to be predicted. In addition, we can calculate KSCC and stress intensity factor in the pipeline caused by EAC.
Abstract: Due to the non-linear characteristics of photovoltaic
(PV) array, PV systems typically are equipped with the capability of
maximum power point tracking (MPPT) feature. Moreover, in the
case of PV array under partially shaded conditions, hotspot problem
will occur which could damage the PV cells. Partial shading causes
multiple peaks in the P-V characteristic curves. This paper presents a
hybrid algorithm of Particle Swarm Optimization (PSO) and
Artificial Neural Network (ANN) MPPT algorithm for the detection
of global peak among the multiple peaks in order to extract the true
maximum energy from PV panel. The PV system consists of PV
array, dc-dc boost converter controlled by the proposed MPPT
algorithm and a resistive load. The system was simulated using
MATLAB/Simulink package. The simulation results show that the
proposed algorithm performs well to detect the true global peak
power. The results of the simulations are analyzed and discussed.
Abstract: The paper proposes a way of parallel processing of
SURF and Optical Flow for moving object recognition and tracking.
The object recognition and tracking is one of the most important task
in computer vision, however disadvantage are many operations cause
processing speed slower so that it can-t do real-time object recognition
and tracking. The proposed method uses a typical way of feature
extraction SURF and moving object Optical Flow for reduce
disadvantage and real-time moving object recognition and tracking,
and parallel processing techniques for speed improvement. First
analyse that an image from DB and acquired through the camera using
SURF for compared to the same object recognition then set ROI
(Region of Interest) for tracking movement of feature points using
Optical Flow. Secondly, using Multi-Thread is for improved
processing speed and recognition by parallel processing. Finally,
performance is evaluated and verified efficiency of algorithm
throughout the experiment.
Abstract: A research program is conducted to evaluate the
mechanical properties of Ultra High Performance Concrete, target
compressive strength at the age of 28 days being more than 150 MPa.
The methodology to develop such mix has been explained. The
material properties, mix design and curing regime are determined.
The material attributes are understood by studying the stress strain
behaviour of UHPC cylinders under uniaxial compressive loading.
The load –crack mouth opening displacement (cmod) of UHPC
beams, flexural strength and fracture energy was evaluated using
third point loading test. Compressive strength and Split tensile
strength results are determined to find out the compressive and tensile
behaviour. Residual strength parameters are presented vividly
explaining the flexural performance, toughness of concrete.Durability
studies were also done to compare the effect of fibre to that of a
control mix For all the studies the Mechanical properties were
evaluated by varying the percentage and aspect ratio of steel fibres
The results reflected that higher aspect ratio and fibre volume
produced drastic changes in the cube strength, cylinder strength, post
peak response, load-cmod, fracture energy flexural strength, split
tensile strength, residual strength and durability. In regards to null
application of UHPC in India, an initiative is undertaken to
comprehend the mechanical behaviour of UHPC, which will be vital
for longer run in commercialization for structural applications.
Abstract: Fracture process in mechanically loaded steel fiber
reinforced high-strength (SFRHSC) concrete is characterized by
fibers bridging the crack providing resistance to its opening.
Structural SFRHSC fracture model was created; material fracture
process was modeled, based on single fiber pull-out laws, which were
determined experimentally (for straight fibers, fibers with end hooks
(Dramix), and corrugated fibers (Tabix)) as well as obtained
numerically ( using FEM simulations). For this purpose experimental
program was realized and pull-out force versus pull-out fiber length
was obtained (for fibers embedded into concrete at different depth
and under different angle). Model predictions were validated by
15x15x60cm prisms 4 point bending tests. Fracture surfaces analysis
was realized for broken prisms with the goal to improve elaborated
model assumptions. Optimal SFRHSC structures were recognized.
Abstract: Repetitive systems stand for a kind of systems that
perform a simple task on a fixed pattern repetitively, which are
widely spread in industrial fields. Hence, many researchers have been
interested in those systems, especially in the field of iterative learning
control (ILC). In this paper, we propose a finite-horizon tracking
control scheme for linear time-varying repetitive systems with uncertain
initial conditions. The scheme is derived both analytically
and numerically for state-feedback systems and only numerically for
output-feedback systems. Then, it is extended to stable systems with
input constraints. All numerical schemes are developed in the forms
of linear matrix inequalities (LMIs). A distinguished feature of the
proposed scheme from the existing iterative learning control is that
the scheme guarantees the tracking performance exactly even under
uncertain initial conditions. The simulation results demonstrate the
good performance of the proposed scheme.
Abstract: the work contains the results of complex investigation
related to the evaluation of condition of working blades of gas turbine
engines during fatigue tests by applying the acoustic emission
method. It demonstrates the possibility of estimating the fatigue
damage of blades in the process of factory tests. The acoustic
emission criteria for detecting and testing the kinetics of fatigue crack
distribution were detected. It also shows the high effectiveness of the
method for non-destructive testing of condition of solid and cooled
working blades for high-temperature gas turbine engines.
Abstract: The world demand for potable water is
increasing every day with growing population. Desalination
using solar energy is suitable for potable water production
from brackish and seawater. In this paper, we present a
theoretical study of solar distillation in a single basin under
the open environmental conditions of Chabahar-Iran. The still
has a base area of 2000mm×500mm with a glass cover
inclined at 25° in order to obtain extra solar energy. We model
the still and conduct its energy balance equations under minor
assumptions. We computed the temperatures of glass cover,
seawater interface, moist air and bottom using numerical
method. The investigation addressed the following: The still
productivity, distilled water salinity and still performance in
terms of the still efficiency. Calculated still productivity in
July was higher than December. So in this paper, we show
that still productivity is directly functioning of solar radiation.
Abstract: This paper presents an algorithm for the recognition
and tracking of moving objects, 1/10 scale model car is used to verify
performance of the algorithm. Presented algorithm for the recognition
and tracking of moving objects in the paper is as follows. SURF
algorithm is merged with Lucas-Kanade algorithm. SURF algorithm
has strong performance on contrast, size, rotation changes and it
recognizes objects but it is slow due to many computational
complexities. Processing speed of Lucas-Kanade algorithm is fast but
the recognition of objects is impossible. Its optical flow compares the
previous and current frames so that can track the movement of a pixel.
The fusion algorithm is created in order to solve problems which
occurred using the Kalman Filter to estimate the position and the
accumulated error compensation algorithm was implemented. Kalman
filter is used to create presented algorithm to complement problems
that is occurred when fusion two algorithms. Kalman filter is used to
estimate next location, compensate for the accumulated error. The
resolution of the camera (Vision Sensor) is fixed to be 640x480. To
verify the performance of the fusion algorithm, test is compared to
SURF algorithm under three situations, driving straight, curve, and
recognizing cars behind the obstacles. Situation similar to the actual is
possible using a model vehicle. Proposed fusion algorithm showed
superior performance and accuracy than the existing object
recognition and tracking algorithms. We will improve the performance
of the algorithm, so that you can experiment with the images of the
actual road environment.
Abstract: A four-lobe pressure dam bearing which is
produced by cutting two pressure dams on the upper two lobes and
two relief-tracks on the lower two lobes of an ordinary four-lobe
bearing is found to be more stable than a conventional four-lobe
bearing. In this paper a four-lobe pressure dam bearing supporting
rigid and flexible rotors is analytically investigated to determine its
performance when L/D ratio is varied in the range 0.75 to 1.5. The
static and dynamic characteristics are studied at various L/D ratios.
The results show that the stability of a four-lobe pressure dam
bearing increases with decrease in L/D ratios both for rigid as well as
flexible rotors.
Abstract: The least mean square (LMS) algorithmis one of the
most well-known algorithms for mobile communication systems
due to its implementation simplicity. However, the main limitation
is its relatively slow convergence rate. In this paper, a booster
using the concept of Markov chains is proposed to speed up the
convergence rate of LMS algorithms. The nature of Markov
chains makes it possible to exploit the past information in the
updating process. Moreover, since the transition matrix has a
smaller variance than that of the weight itself by the central limit
theorem, the weight transition matrix converges faster than the
weight itself. Accordingly, the proposed Markov-chain based
booster thus has the ability to track variations in signal
characteristics, and meanwhile, it can accelerate the rate of
convergence for LMS algorithms. Simulation results show that the
LMS algorithm can effectively increase the convergence rate and
meantime further approach the Wiener solution, if the
Markov-chain based booster is applied. The mean square error is
also remarkably reduced, while the convergence rate is improved.
Abstract: Subdivision is a method to create a smooth surface from a coarse mesh by subdividing the entire mesh. The conventional ways to compute and render surfaces are inconvenient both in terms of memory and computational time as the number of meshes will increase exponentially. An adaptive subdivision is the way to reduce the computational time and memory by subdividing only certain selected areas. In this paper, a new adaptive subdivision method for triangle meshes is introduced. This method defines a new adaptive subdivision rules by considering the properties of each triangle's neighbors and is embedded in a traditional Loop's subdivision. It prevents some undesirable side effects that appear in the conventional adaptive ways. Models that were subdivided by our method are compared with other adaptive subdivision methods
Abstract: The present paper proposes high performance nonlinear
force controllers for a servopneumatic real-time fatigue test
machine. A CompactRIO® controller was used, being fully
programmed using LabVIEW language. Fuzzy logic control
algorithms were evaluated to tune the integral and derivative
components in the development of hybrid controllers, namely a FLC
P and a hybrid FLC PID real-time-based controllers. Their
behaviours were described by using state diagrams. The main
contribution is to ensure a smooth transition between control states,
avoiding discrete transitions in controller outputs. Steady-state errors
lower than 1.5 N were reached, without retuning the controllers.
Good results were also obtained for sinusoidal tracking tasks from
1/¤Ç to 8/¤Ç Hz.