Abstract: The objective of this study is to propose an observer design for nonlinear systems by using an augmented linear system derived by application of a formal linearization method. A given nonlinear differential equation is linearized by the formal linearization method which is based on Taylor expansion considering up to the higher order terms, and a measurement equation is transformed into an augmented linear one. To this augmented dimensional linear system, a linear estimation theory is applied and a nonlinear observer is derived. As an application of this method, an estimation problem of transient state of electric power systems is studied, and its numerical experiments indicate that this observer design shows remarkable performances for nonlinear systems.
Abstract: This article presents a current-mode quadrature
oscillator using differential different current conveyor (DDCC) and
voltage differencing transconductance amplifier (VDTA) as active
elements. The proposed circuit is realized fro m a non-inverting
lossless integrator and an inverting second order low-pass filter. The
oscillation condition and oscillation frequency can be
electronically/orthogonally controlled via input bias currents. The
circuit description is very simple, consisting of merely 1 DDCC, 1
VDTA, 1 grounded resistor and 3 grounded capacitors. Using only
grounded elements, the proposed circuit is then suitable for IC
architecture. The proposed oscillator has high output impedance
which is easy to cascade or dive the external load without the buffer
devices. The PSPICE simulation results are depicted, and the given
results agree well with the theoretical anticipation. The power
consumption is approximately 1.76mW at ±1.25V supply voltages.
Abstract: In Multiple Sclerosis, pathological changes in the
brain results in deviations in signal intensity on Magnetic Resonance
Images (MRI). Quantitative analysis of these changes and their
correlation with clinical finding provides important information for
diagnosis. This constitutes the objective of our work. A new approach
is developed. After the enhancement of images contrast and the brain
extraction by mathematical morphology algorithm, we proceed to the
brain segmentation. Our approach is based on building statistical
model from data itself, for normal brain MRI and including clustering
tissue type. Then we detect signal abnormalities (MS lesions) as a
rejection class containing voxels that are not explained by the built
model. We validate the method on MR images of Multiple Sclerosis
patients by comparing its results with those of human expert
segmentation.
Abstract: This study investigated the relationship between
exercise imagery use and level of physical activity within a wide
range of exercisers in Klang valley, Malaysia. One hundred and
twenty four respondents (Mage = 28.92, SD = 9.34) completed two
sets of questionnaires (Exercise Imagery Inventory and Leisure-Time
Exercise Questionnaire) that measure the use of imagery and exercise
frequency of participants. From the result obtained, exercise imagery
is found to be significantly correlated to level of physical activity.
Besides that, variables such as gender, age and ethnicity that may
affect the use of imagery and exercise frequency were also being
assessed in this study. Among all variables, only ethnicity showed
significant difference in level of physical activity (p < 0.05). Findings
in this study suggest that further investigation should be done on
other variables such as socioeconomic, educational level, and selfefficacy
that may affect the imagery use and frequency of physical
activity among exercisers.
Abstract: Topics Disaster and Emergency Management are highly debated among experts. Fast communication will help to deal with emergencies. Problem is with the network connection and data exchange. The paper suggests a solution, which allows possibilities and perspectives of new flexible communication platform to the protection of communication systems for crisis management. This platform is used for everyday communication and communication in crisis situations too.
Abstract: The crop rice is the staple food of most Sierra Leone
with no close substitute. However, its cultivation has been on its last
legs over the years. The decline in the domestic rice cultivation has
had vicious socio-economic implications such as hiking consumer
prices, balance of payment dilemmas with debt burden. The objective
of this study is thus, to assess the effect of the shift of rural labour
towards non-agricultural sectors on rice cultivation. The tools utilized
for analyzing the problem under consideration involved a thorough
descriptive statistics and generalized linear model using OLS
technique. Increased rural population was established positive and
significant in affecting rice cultivation. Fertilizer utilization was
insignificant in rice cultivation. For reducing the shift of rural labor
force towards nonagricultural sectors, the government should make
the agricultural sector very lucrative.
Abstract: Cameron Highlands is a mountainous area subjected
to torrential tropical showers. It extracts 5.8 million liters of water
per day for drinking supply from its rivers at several intake points.
The water quality of rivers in Cameron Highlands, however, has
deteriorated significantly due to land clearing for agriculture,
excessive usage of pesticides and fertilizers as well as construction
activities in rapidly developing urban areas. On the other hand, these
pollution sources known as non-point pollution sources are diverse
and hard to identify and therefore they are difficult to estimate.
Hence, Geographical Information Systems (GIS) was used to provide
an extensive approach to evaluate landuse and other mapping
characteristics to explain the spatial distribution of non-point sources
of contamination in Cameron Highlands. The method to assess
pollution sources has been developed by using Cameron Highlands
Master Plan (2006-2010) for integrating GIS, databases, as well as
pollution loads in the area of study. The results show highest annual
runoff is created by forest, 3.56 × 108 m3/yr followed by urban
development, 1.46 × 108 m3/yr. Furthermore, urban development
causes highest BOD load (1.31 × 106 kgBOD/yr) while agricultural
activities and forest contribute the highest annual loads for
phosphorus (6.91 × 104 kgP/yr) and nitrogen (2.50 × 105 kgN/yr),
respectively. Therefore, best management practices (BMPs) are
suggested to be applied to reduce pollution level in the area.
Abstract: The vehicle routing problem (VRP) is a famous combinatorial optimization problem. Because of its well-known difficulty, metaheuristics are the most appropriate methods to tackle large and realistic instances. The goal of this paper is to highlight the key ideas for designing VRP metaheuristics according to the following criteria: efficiency, speed, robustness, and ability to take advantage of the problem structure. Such elements can obviously be used to build solution methods for other combinatorial optimization problems, at least in the deterministic field.
Abstract: When the foundations of structures under cyclic
loading with amplitudes less than their permissible load, the concern exists often for the amount of uniform and non-uniform settlement of
such structures. Storage tank foundations with numerous filling and discharging and railways ballast course under repeating
transportation loads are examples of such conditions. This paper
deals with the effects of using the new generation of reinforcements,
Grid-Anchor, for the purpose of reducing the permanent settlement
of these foundations under the influence of different proportions of
the ultimate load. Other items such as the type and the number of
reinforcements as well as the number of loading cycles are studied numerically. Numerical models were made using the Plaxis3D
Tunnel finite element code. The results show that by using gridanchor
and increasing the number of their layers in the same
proportion as that of the cyclic load being applied, the amount of
permanent settlement decreases up to 42% relative to unreinforced
condition depends on the number of reinforcement layers and percent
of applied load and the number of loading cycles to reach a constant
value of dimensionless settlement decreases up to 20% relative to
unreinforced condition.
Abstract: In recent years, a number of works proposing the
combination of multiple classifiers to produce a single
classification have been reported in remote sensing literature. The
resulting classifier, referred to as an ensemble classifier, is
generally found to be more accurate than any of the individual
classifiers making up the ensemble. As accuracy is the primary
concern, much of the research in the field of land cover
classification is focused on improving classification accuracy. This
study compares the performance of four ensemble approaches
(boosting, bagging, DECORATE and random subspace) with a
univariate decision tree as base classifier. Two training datasets,
one without ant noise and other with 20 percent noise was used to
judge the performance of different ensemble approaches. Results
with noise free data set suggest an improvement of about 4% in
classification accuracy with all ensemble approaches in
comparison to the results provided by univariate decision tree
classifier. Highest classification accuracy of 87.43% was achieved
by boosted decision tree. A comparison of results with noisy data
set suggests that bagging, DECORATE and random subspace
approaches works well with this data whereas the performance of
boosted decision tree degrades and a classification accuracy of
79.7% is achieved which is even lower than that is achieved (i.e.
80.02%) by using unboosted decision tree classifier.
Abstract: This paper presents a numerical analysis of the
performance of a five-bladed Darrieus vertical-axis water turbine,
based on the NACA 0025 blade profile, for both bare and shrouded
configurations. A complete campaign of 2-D simulations, performed
for several values of tip speed ratio and based on RANS unsteady
calculations, has been performed to obtain the rotor torque and power
curves. Also the effect of a NACA-shaped central hydrofoil has been
investigated, with the aim of evaluating the impact of a solid
blockage on the performance of the shrouded rotor configuration.
The beneficial effect of the shroud on rotor overall performances
has clearly been evidenced, while the adoption of the central
hydrofoil has proved to be detrimental, being the resulting flow slow
down (due to the presence of the obstacle) much higher with respect
to the flow acceleration (due to the solid blockage effect).
Abstract: Minimally invasive surgery (MIS) is now being widely used as a preferred choice for various types of operations. The need to detect various tactile properties, justifies the key role of tactile sensing that is currently missing in MIS. In this regard, Laparoscopy is one of the methods of minimally invasive surgery that can be used in kidney stone removal surgeries. At this moment, determination of the exact location of stone during laparoscopy is one of the limitations of this method that no scientific solution has been found for so far. Artificial tactile sensing is a new method for obtaining the characteristics of a hard object embedded in a soft tissue. Artificial palpation is an important application of artificial tactile sensing that can be used in different types of surgeries. In this study, a new method for determining the exact location of stone during laparoscopy is presented. In the present study, the effects of stone existence on the surface of kidney were investigated using conceptual 3D model of kidney containing a simulated stone. Having imitated palpation and modeled it conceptually, indications of stone existence that appear on the surface of kidney were determined. A number of different cases were created and solved by the software and using stress distribution contours and stress graphs, it is illustrated that the created stress patterns on the surface of kidney show not only the existence of stone inside, but also its exact location. So three-dimensional analysis leads to a novel method of predicting the exact location of stone and can be directly applied to the incorporation of tactile sensing in artificial palpation, helping surgeons in non-invasive procedures.
Abstract: In this paper, the full state feedback controllers
capable of regulating and tracking the speed trajectory are presented.
A fourth order nonlinear mean value model of a 448 kW turbocharged
diesel engine published earlier is used for the purpose.
For designing controllers, the nonlinear model is linearized and
represented in state-space form. Full state feedback controllers
capable of meeting varying speed demands of drivers are presented.
Main focus here is to investigate sensitivity of the controller to the
perturbations in the parameters of the original nonlinear model.
Suggested controller is shown to be highly insensitive to the
parameter variations. This indicates that the controller is likely
perform with same accuracy even after significant wear and tear of
engine due to its use for years.
Abstract: In this paper, different approaches to solve the
forward kinematics of a three DOF actuator redundant hydraulic
parallel manipulator are presented. On the contrary to series
manipulators, the forward kinematic map of parallel manipulators
involves highly coupled nonlinear equations, which are almost
impossible to solve analytically. The proposed methods are using
neural networks identification with different structures to solve the
problem. The accuracy of the results of each method is analyzed in
detail and the advantages and the disadvantages of them in
computing the forward kinematic map of the given mechanism is
discussed in detail. It is concluded that ANFIS presents the best
performance compared to MLP, RBF and PNN networks in this
particular application.
Abstract: Heart failure is the most common reason of death
nowadays, but if the medical help is given directly, the patient-s life
may be saved in many cases. Numerous heart diseases can be
detected by means of analyzing electrocardiograms (ECG). Artificial
Neural Networks (ANN) are computer-based expert systems that
have proved to be useful in pattern recognition tasks. ANN can be
used in different phases of the decision-making process, from
classification to diagnostic procedures. This work concentrates on a
review followed by a novel method.
The purpose of the review is to assess the evidence of healthcare
benefits involving the application of artificial neural networks to the
clinical functions of diagnosis, prognosis and survival analysis, in
ECG signals. The developed method is based on a compound neural
network (CNN), to classify ECGs as normal or carrying an
AtrioVentricular heart Block (AVB). This method uses three
different feed forward multilayer neural networks. A single output
unit encodes the probability of AVB occurrences. A value between 0
and 0.1 is the desired output for a normal ECG; a value between 0.1
and 1 would infer an occurrence of an AVB. The results show that
this compound network has a good performance in detecting AVBs,
with a sensitivity of 90.7% and a specificity of 86.05%. The accuracy
value is 87.9%.
Abstract: In this study, we propose a network architecture for
providing secure access to information resources of enterprise
network from remote locations in a wireless fashion. Our proposed
architecture offers a very promising solution for organizations which
are in need of a secure, flexible and cost-effective remote access
methodology. Security of the proposed architecture is based on
Virtual Private Network technology and a special role based access
control mechanism with location and time constraints. The flexibility
mainly comes from the use of Internet as the communication medium
and cost-effectiveness is due to the possibility of in-house
implementation of the proposed architecture.
Abstract: This paper presents a system overview of Mobile to Server Face Recognition, which is a face recognition application developed specifically for mobile phones. Images taken from mobile phone cameras lack of quality due to the low resolution of the cameras. Thus, a prototype is developed to experiment the chosen method. However, this paper shows a result of system backbone without the face recognition functionality. The result demonstrated in this paper indicates that the interaction between mobile phones and server is successfully working. The result shown before the database is completely ready. The system testing is currently going on using real images and a mock-up database to test the functionality of the face recognition algorithm used in this system. An overview of the whole system including screenshots and system flow-chart are presented in this paper. This paper also presents the inspiration or motivation and the justification in developing this system.
Abstract: The study in this paper underlines the importance of
correct joint selection of the spreading codes for uplink of multicarrier
code division multiple access (MC-CDMA) at the transmitter
side and detector at the receiver side in the presence of nonlinear
distortion due to high power amplifier (HPA). The bit error rate
(BER) of system for different spreading sequences (Walsh code, Gold
code, orthogonal Gold code, Golay code and Zadoff-Chu code) and
different kinds of receivers (minimum mean-square error receiver
(MMSE-MUD) and microstatistic multi-user receiver (MSF-MUD))
is compared by means of simulations for MC-CDMA transmission
system. Finally, the results of analysis will show, that the application
of MSF-MUD in combination with Golay codes can outperform
significantly the other tested spreading codes and receivers for all
mostly used models of HPA.
Abstract: This article presents the simulation, parameterization and optimization of an electromagnet with the C–shaped configuration, intended for the study of magnetic properties of materials. The electromagnet studied consists of a C-shaped yoke, which provides self–shielding for minimizing losses of magnetic flux density, two poles of high magnetic permeability and power coils wound on the poles. The main physical variable studied was the static magnetic flux density in a column within the gap between the poles, with 4cm2 of square cross section and a length of 5cm, seeking a suitable set of parameters that allow us to achieve a uniform magnetic flux density of 1x104 Gaussor values above this in the column, when the system operates at room temperature and with a current consumption not exceeding 5A. By means of a magnetostatic analysis by the finite element method, the magnetic flux density and the distribution of the magnetic field lines were visualized and quantified. From the results obtained by simulating an initial configuration of electromagnet, a structural optimization of the geometry of the adjustable caps for the ends of the poles was performed. The magnetic permeability effect of the soft magnetic materials used in the poles system, such as low– carbon steel (0.08% C), Permalloy (45% Ni, 54.7% Fe) and Mumetal (21.2% Fe, 78.5% Ni), was also evaluated. The intensity and uniformity of the magnetic field in the gap showed a high dependence with the factors described above. The magnetic field achieved in the column was uniform and its magnitude ranged between 1.5x104 Gauss and 1.9x104 Gauss according to the material of the pole used, with the possibility of increasing the magnetic field by choosing a suitable geometry of the cap, introducing a cooling system for the coils and adjusting the spacing between the poles. This makes the device a versatile and scalable tool to generate the magnetic field necessary to perform magnetic characterization of materials by techniques such as vibrating sample magnetometry (VSM), Hall-effect, Kerr-effect magnetometry, among others. Additionally, a CAD design of the modules of the electromagnet is presented in order to facilitate the construction and scaling of the physical device.
Abstract: In this paper, an adaptive radio resource allocation
(RRA) algorithm applying to multiple traffic OFDMA system is
proposed, which distributes sub-carrier and loading bits among users
according to their different QoS requirements and traffic class. By
classifying and prioritizing the users based on their traffic
characteristic and ensuring resource for higher priority users, the
scheme decreases tremendously the outage probability of the users
requiring a real time transmission without impact on the spectrum
efficiency of system, as well as the outage probability of data users is
not increased compared with the RRA methods published.