Abstract: We present a simplified equalization technique for a
π/4 differential quadrature phase shift keying ( π/4 -DQPSK) modulated
signal in a multipath fading environment. The proposed equalizer is
realized as a fractionally spaced adaptive decision feedback equalizer
(FS-ADFE), employing exponential step-size least mean square
(LMS) algorithm as the adaptation technique. The main advantage of
the scheme stems from the usage of exponential step-size LMS algorithm
in the equalizer, which achieves similar convergence behavior
as that of a recursive least squares (RLS) algorithm with significantly
reduced computational complexity. To investigate the finite-precision
performance of the proposed equalizer along with the π/4 -DQPSK
modem, the entire system is evaluated on a 16-bit fixed point digital
signal processor (DSP) environment. The proposed scheme is found
to be attractive even for those cases where equalization is to be
performed within a restricted number of training samples.
Abstract: This paper proposes a synchronized random switching frequency pulse width modulation (SRSFPWM). In this technique, the clock signal is used to control the random noise frequency which is produced by the feedback voltage of a hysteresis circuit. These make the triangular carrier frequency equaling to the random noise frequency in each switching period with the symmetrical positive and negative slopes of triangular carrier. Therefore, there is no error voltage in PWM signal. The PSpice simulated results shown the proposed technique improved the performance in case of low frequency harmonics of PWM signal comparing with conventional random switching frequency PWM.
Abstract: In this paper, stability and Hopf bifurcation analysis of
a novel hyperchaotic system are investigated. Four feedback control
strategies, the linear feedback control method, enhancing feedback
control method, speed feedback control method and delayed feedback
control method, are used to control the hyperchaotic attractor to
unstable equilibrium. Moreover numerical simulations are given to
verify the theoretical results.
Abstract: Saccharomyces cerevisiae (baker-s yeast) can exhibit
sustained oscillations during the operation in a continuous bioreactor
that adversely affects its stability and productivity. Because of
heterogeneous nature of cell populations, the cell population balance
models can be used to capture the dynamic behavior of such cultures.
In this paper an unstructured, segregated model is used which is
based on population balance equation(PBE) and then in order to
simulation, the 4th order Rung-Kutta is used for time dimension and
three methods, finite difference, orthogonal collocation on finite
elements and Galerkin finite element are used for discretization of the
cell mass domain. The results indicate that the orthogonal collocation
on finite element not only is able to predict the oscillating behavior of
the cell culture but also needs much little time for calculations.
Therefore this method is preferred in comparison with other methods.
In the next step two controllers, a globally linearizing control (GLC)
and a conventional proportional-integral (PI) controller are designed
for controlling the total cell mass per unit volume, and performances
of these controllers are compared through simulation. The results
show that although the PI controller has simpler structure, the GLC
has better performance.
Abstract: The Learning Management Systems present learning
environment which offers a collection of e-learning tools in a
package that allows a common interface and information sharing
among the tools. South East European University initial experience
in LMS was with the usage of the commercial LMS-ANGEL. After a
three year experience on ANGEL usage because of expenses that
were very high it was decided to develop our own software. As part
of the research project team for the in-house design and development
of the new LMS, we primarily had to select the features that would
cover our needs and also comply with the actual trends in the area of
software development, and then design and develop the system. In
this paper we present the process of LMS in-house development for
South East European University, its architecture, conception and
strengths with a special accent on the process of migration and
integration with other enterprise applications.
Abstract: This paper presents a design method of self-tuning
Quantitative Feedback Theory (QFT) by using improved deadbeat
control algorithm. QFT is a technique to achieve robust control with
pre-defined specifications whereas deadbeat is an algorithm that
could bring the output to steady state with minimum step size.
Nevertheless, usually there are large peaks in the deadbeat response.
By integrating QFT specifications into deadbeat algorithm, the large
peaks could be tolerated. On the other hand, emerging QFT with
adaptive element will produce a robust controller with wider
coverage of uncertainty. By combining QFT-based deadbeat
algorithm and adaptive element, superior controller that is called selftuning
QFT-based deadbeat controller could be achieved. The output
response that is fast, robust and adaptive is expected. Using a grain
dryer plant model as a pilot case-study, the performance of the
proposed method has been evaluated and analyzed. Grain drying
process is very complex with highly nonlinear behaviour, long delay,
affected by environmental changes and affected by disturbances.
Performance comparisons have been performed between the
proposed self-tuning QFT-based deadbeat, standard QFT and
standard dead-beat controllers. The efficiency of the self-tuning QFTbased
dead-beat controller has been proven from the tests results in
terms of controller’s parameters are updated online, less percentage
of overshoot and settling time especially when there are variations in
the plant.
Abstract: This paper at first presents approximate analytical
solutions for systems of fractional differential equations using the
differential transform method. The application of differential
transform method, developed for differential equations of integer
order, is extended to derive approximate analytical solutions of
systems of fractional differential equations. The solutions of our
model equations are calculated in the form of convergent series with
easily computable components. After that a drive-response
synchronization method with linear output error feedback is
presented for “generalized projective synchronization" for a class of
fractional-order chaotic systems via a scalar transmitted signal.
Genesio_Tesi and Duffing systems are used to illustrate the
effectiveness of the proposed synchronization method.
Abstract: The controllable electrical loss which consists of the
copper loss and iron loss can be minimized by the optimal control of
the armature current vector. The control algorithm of current vector
minimizing the electrical loss is proposed and the optimal current
vector can be decided according to the operating speed and the load
conditions. The proposed control algorithm is applied to the
experimental PM motor drive system and this paper presents a
modern approach of speed control for permanent magnet
synchronous motor (PMSM) applied for Electric Vehicle using a
nonlinear control. The regulation algorithms are based on the
feedback linearization technique. The direct component of the current
is controlled to be zero which insures the maximum torque operation.
The near unity power factor operation is also achieved. More over,
among EV-s motor electric propulsion features, the energy efficiency
is a basic characteristic that is influenced by vehicle dynamics and
system architecture. For this reason, the EV dynamics are taken into
account.
Abstract: The result of process of territory-s development is the territory-s state of development (TSoD), which is pointed towards the provision and improvement of people-s life conditions. The authors offer to measure the TSoD according to their own developed model. Using the available statistical data regarding the values of model-s elements, the authors empirically show which element mainly determines the TSoD. The findings of the research showed that the key elements of the TSoD are the “Material welfare of people" and “People-s health". Performing a deeper statistical analysis of correlation between these elements, it turned out that it is not so necessary for a country to be bent on trying to increase the material growth of a territory, because a relatively high index of life expectancy at birth could be ensured also by much more modest material resources. On the other hand, the economical feedback of longer lifespan within countries with lower material performance is also relatively low.
Abstract: A nonlinear optimal controller with a fuzzy gain
scheduler has been designed and applied to a Line-Of-Sight (LOS)
stabilization system. Use of Linear Quadratic Regulator (LQR)
theory is an optimal and simple manner of solving many control
engineering problems. However, this method cannot be utilized
directly for multigimbal LOS systems since they are nonlinear in
nature. To adapt LQ controllers to nonlinear systems at least a
linearization of the model plant is required. When the linearized
model is only valid within the vicinity of an operating point a gain
scheduler is required. Therefore, a Takagi-Sugeno Fuzzy Inference
System gain scheduler has been implemented, which keeps the
asymptotic stability performance provided by the optimal feedback
gain approach. The simulation results illustrate that the proposed
controller is capable of overcoming disturbances and maintaining a
satisfactory tracking performance.
Abstract: In this paper, we give an overview of an online elearning
tool which has been developed for kids aged from nine to
eleven years old in Mauritius for the self-study of Mathematics in
order to prepare them for the CPE examination. The software does
not intend to render obsolete the existing pedagogical approaches.
Nowadays, the teaching-learning process is mainly focused towards
the class-room model. Moreover, most of the e-learning platforms
that exist are simply static ways of delivering resources using the
internet. There is nearly no interaction between the learner and the
tool. Our application will enable students to practice exercises online
and also work out sample examination papers. Another interesting
feature is that the kid will not have to wait for someone to correct the
work as the correction will be done online and on the spot. Additional
feedback is also provided for some exercises.
Abstract: Recent research result has shown that two multidelay
feedback systems can synchronize each other under different
schemes, i.e. lag, projective-lag, anticipating, or projectiveanticipating
synchronization. There, the driving signal is significantly
complex due that it is constituted by multiple nonlinear transformations
of delayed state variable. In this paper, a secure communication
model is proposed based on synchronization of coupled multidelay
feedback systems, in which the plain signal is mixed with a complex
signal at the transmitter side and it is precisely retrieved at the receiver
side. The effectiveness of the proposed model is demonstrated and
verified in the specific example, where the message signal is masked
directly by the complex signal and security is examined under the
breaking method of power spectrum analysis.
Abstract: Unstructured peer-to-peer networks are popular due to
its robustness and scalability. Query schemes that are being used in
unstructured peer-to-peer such as the flooding and interest-based
shortcuts suffer various problems such as using large communication
overhead long delay response. The use of routing indices has been a
popular approach for peer-to-peer query routing. It helps the query
routing processes to learn the routing based on the feedbacks
collected. In an unstructured network where there is no global
information available, efficient and low cost routing approach is
needed for routing efficiency.
In this paper, we propose a novel mechanism for query-feedback
oriented routing indices to achieve routing efficiency in unstructured
network at a minimal cost. The approach also applied information
retrieval technique to make sure the content of the query is
understandable and will make the routing process not just based to
the query hits but also related to the query content. Experiments have
shown that the proposed mechanism performs more efficient than
flood-based routing.
Abstract: Pharmacology curriculum plays an integral role in
medical education. Learning pharmacology to choose and prescribe
drugs is a major challenge encountered by students. We developed
pharmacology applied learning activities for first year medical
students that included realistic clinical situations with escalating
complications which required the students to analyze the situation
and think critically to choose a safe drug. Tutor feedback was
provided at the end of session. Evaluation was done to assess the
students- level of interest and usefulness of the sessions in rational
selection of drugs. Majority (98 %) of the students agreed that the
session was an extremely useful learning exercise and agreed that
similar sessions would help in rational selection of drugs. Applied
learning sessions in the early years of medical program may promote
deep learning and bridge the gap between pharmacology theory and
clinical practice. Besides, it may also enhance safe prescribing skills.
Abstract: With getting older in the whole population, the
prevalence of stroke and its residual disability is getting higher and
higher recently in Taiwan. The functional electrical stimulation
cycling system (FESCS) is useful for hemiplegic patients. Because
that the muscle of stroke patients is under hybrid activation. The raw
electromyography (EMG) represents the residual muscle force of
stroke subject whereas the peak-to-peak of stimulus EMG indicates the
force enhancement benefiting from ES. It seems that EMG signals
could be used for a parameter of feedback control mechanism. So, we
design the feedback control protocol of FESCS, it includes
physiological signal recorder, FPGA biomedical module, DAC and
electrical stimulation circuit. Using the intensity of real-time EMG
signal obtained from patients, as a feedback control method for the
output voltage of FES-cycling system.
Abstract: A dynamic risk management framework for software
projects is presented. Currently available software risk management
frameworks and risk assessment models are static in nature and lacks
feedback capability. Such risk management frameworks are not
capable of providing the risk assessment of futuristic changes in risk
events. A dynamic risk management framework for software project
is needed that provides futuristic assessment of risk events.
Abstract: If organizations like Mellat Bank want to identify its
customer market completely to reach its specified goals, it can
segment the market to offer the product package to the right segment.
Our objective is to offer a segmentation model for Iran banking
market in Mellat bank view. The methodology of this project is
combined by “segmentation on the basis of four part-quality
variables" and “segmentation on the basis of different in means".
Required data are gathered from E-Systems and researcher personal
observation. Finally, the research offers the organization that at first
step form a four dimensional matrix with 756 segments using four
variables named value-based, behavioral, activity style, and activity
level, and at the second step calculate the means of profit for every
cell of matrix in two distinguished work level (levels α1:normal
condition and α2: high pressure condition) and compare the segments
by checking two conditions that are 1- homogeneity every segment
with its sub segment and 2- heterogeneity with other segments, and
so it can do the necessary segmentation process. After all, the last
offer (more explained by an operational example and feedback
algorithm) is to test and update the model because of dynamic
environment, technology, and banking system.
Abstract: This paper presents a wrap-around view system with 4
smart cameras module and remote motion mobile robot control equipped with smart camera module system. The two-level scheme for
remote motion control with smart-pad(IPAD) is introduced on this
paper. In the low-level, the wrap-around view system is controlled or operated to keep the reference points lying around top view image
plane. On the higher level, a robot image based motion controller is utilized to drive the mobile platform to reach the desired position or
track the desired motion planning through image feature feedback. The
design wrap-around view system equipped on presents such advantages as follows: 1) a satisfactory solution for the FOV and affine
problem; 2) free of any complex and constraint with robot pose. The performance of the wrap-around view equipped on mobile robot
remote control is proven by experimental results.
Abstract: A multivariable discontinuous feedback linearization approach is proposed to position control of an electrically driven fast robot manipulator. A desired performance is achieved by selecting a useful controller and suitable sampling rate and considering saturation for actuators. There is a high flexibility to apply the proposed control approach on different electrically driven manipulators. The control approach can guarantee the stability and satisfactory tracking performance. A PUMA 560 robot driven by geared permanent magnet dc motors is simulated. The simulation results show a desired performance for control system under technical specifications.
Abstract: In this paper, we consider a food-limited population model with delay and feedback control. By applying the comparison theorem of the differential equation and constructing a suitable Lyapunov functional, sufficient conditions which guarantee the permanence and existence of a unique globally attractive positive almost periodic solution of the system are obtained.