Abstract: Information hiding, especially watermarking is a
promising technique for the protection of intellectual property rights.
This technology is mainly advanced for multimedia but the same has
not been done for text. Web pages, like other documents, need a
protection against piracy. In this paper, some techniques are
proposed to show how to hide information in web pages using some
features of the markup language used to describe these pages. Most
of the techniques proposed here use the white space to hide
information or some varieties of the language in representing
elements. Experiments on a very small page and analysis of five
thousands web pages show that these techniques have a wide
bandwidth available for information hiding, and they might form a
solid base to develop a robust algorithm for web page watermarking.
Abstract: The previous study of new metal gasket that contact
width and contact stress an important design parameter for optimizing
metal gasket performance. The optimum design based on an elastic
and plastic contact stress was founded. However, the influence of
flange surface roughness had not been investigated thoroughly. The
flange has many kinds of surface roughness. In this study, we
conducted a gasket model include a flange surface roughness effect. A
finite element method was employed to develop simulation solution. A
uniform quadratic mesh used for meshing the gasket material and a
gradually quadrilateral mesh used for meshing the flange. The gasket
model was simulated by using two simulation stages which is forming
and tightening simulation. A simulation result shows that a smoother
of surface roughness has higher slope for force per unit length. This
mean a squeezed against between flange and gasket will be strong. The
slope of force per unit length for gasket 400-MPa mode was higher
than the gasket 0-MPa mode.
Abstract: Based on a non-linear single track model which
describes the dynamics of vehicle, an optimal path planning strategy
is developed. Real time optimization is used to generate reference
control values to allow leading the vehicle alongside a calculated lane
which is optimal for different objectives such as energy consumption,
run time, safety or comfort characteristics. Strict mathematic
formulation of the autonomous driving allows taking decision on
undefined situation such as lane change or obstacle avoidance. Based
on position of the vehicle, lane situation and obstacle position, the
optimization problem is reformulated in real-time to avoid the
obstacle and any car crash.
Abstract: An active RC filters with a 880 / 1760 MHz dual bandwidth tuning ability is present for 60 GHz unlicensed band applications. A third order Butterworth low-pass filter utilizes two Cherry-Hooper amplifiers to satisfy the very high bandwidth requirements of an amplifier. The low-pass filter is fabricated in 90nm standard CMOS process. Drawing 6.7 mW from 1.2 V power supply, the low frequency gains of the filter are -2.5 and -4.1 dB, and the output third order intercept points (OIP3) are +2.2 and +1.9 dBm for the single channel and channel bonding conditions, respectively.
Abstract: This paper analytically investigates the 3D flow
pattern at the confluences of two rectangular channels having 900
angles using Navier-Stokes equations based on Reynolds Stress
Turbulence Model (RSM). The equations are solved by the Finite-
Volume Method (FVM) and the flow is analyzed in terms of steadystate
(single-phased) conditions. The Shumate experimental findings
were used to test the validity of data. Comparison of the simulation
model with the experimental ones indicated a close proximity
between the flow patterns of the two sets. Effects of the discharge
ratio on separation zone dimensions created in the main-channel
downstream of the confluence indicated an inverse relation, where a
decrease in discharge ratio, will entail an increase in the length and
width of the separation zone. The study also found the model as a
powerful analytical tool in the feasibility study of hydraulic
engineering projects.
Abstract: This paper presents an optimized methodology to
folded cascode operational transconductance amplifier (OTA) design.
The design is done in different regions of operation, weak inversion,
strong inversion and moderate inversion using the gm/ID methodology
in order to optimize MOS transistor sizing.
Using 0.35μm CMOS process, the designed folded cascode OTA
achieves a DC gain of 77.5dB and a unity-gain frequency of 430MHz
in strong inversion mode. In moderate inversion mode, it has a 92dB
DC gain and provides a gain bandwidth product of around 69MHz.
The OTA circuit has a DC gain of 75.5dB and unity-gain frequency
limited to 19.14MHZ in weak inversion region.
Abstract: Nowadays it is a trend for electronic circuit designers to
integrate all system components on a single-chip. This paper proposed
the design of a single-chip proportional to absolute temperature
(PTAT) sensor including a voltage reference circuit using CEDEC
0.18m CMOS Technology. It is a challenge to design asingle-chip
wide range linear response temperature sensor for many applications.
The channel widths between the compensation transistor and the
reference transistor are critical to design the PTAT temperature sensor
circuit. The designed temperature sensor shows excellent linearity
between -100°C to 200° and the sensitivity is about 0.05mV/°C.
The chip is designed to operate with a single voltage source of 1.6V.
Abstract: This paper describes design of a digital feedback loop
for a low switching frequency dc-dc switching converters. Low
switching frequencies were selected in this design. A look up table
for the digital PID (proportional integrator differentiator)
compensator was implemented using Altera Stratix II with built-in
ADC (analog-to-digital converter) to achieve this hardware
realization. Design guidelines are given for the PID compensator,
high frequency DPWM (digital pulse width modulator) and moving
average filter.
Abstract: Elliptic curve-based certificateless signature is slowly
gaining attention due to its ability to retain the efficiency of
identity-based signature to eliminate the need of certificate
management while it does not suffer from inherent private
key escrow problem. Generally, cryptosystem based on elliptic
curve offers equivalent security strength at smaller key sizes
compared to conventional cryptosystem such as RSA which
results in faster computations and efficient use of computing
power, bandwidth, and storage. This paper proposes to implement
certificateless signature based on bilinear pairing to
structure the framework of IKE authentication. In this paper,
we perform a comparative analysis of certificateless signature
scheme with a well-known RSA scheme and also present the
experimental results in the context of signing and verification
execution times. By generalizing our observations, we discuss the
different trade-offs involved in implementing IKE authentication
by using certificateless signature.
Abstract: Microstrip antennas are conformable to planar and
nonplanar surfaces, simple and inexpensive to fabricate using modern
printed-circuit technology. Circular polarization of low-profile
microstrip patch with high bandwidth is achieved in this research
through the use of a three-cross-arms branch-line coupler with
sequential rotated arrays, another low-profile antenna of hollow
cylinder is also proposed and the function of reconnaissance with
microstrip antenna on Mini UAV (unmanned aerial vehicle) are
evaluated in practical flight test.
Abstract: Space Vector Modulation (SVM) is an optimum Pulse Width Modulation (PWM) technique for an inverter used in a variable frequency drive applications. It is computationally rigorous and hence limits the inverter switching frequency. Increase in switching frequency can be achieved using Neural Network (NN) based SVM, implemented on application specific chips. This paper proposes a neural network based SVM technique for a Voltage Source Inverter (VSI). The network proposed is independent of switching frequency. Different architectures are investigated keeping the total number of neurons constant. The performance of the inverter is compared for various switching frequencies for different architectures of NN based SVM. From the results obtained, the network with minimum resource and appropriate word length is identified. The bit precision required for this application is identified. The network with 8-bit precision is implemented in the IC XCV 400 and the results are presented. The performance of NN based general purpose SVM with higher bit precision is discussed.
Abstract: Research results and optimal parameters investigation
of laser cut and profiling of diamond and quartz substrates by
femtosecond laser pulses are presented. Profiles 10 μm in width, ~25
μm in depth and several millimeters long were made. Investigation of
boundaries quality has been carried out with the use of AFM
«Vecco». Possibility of technological formation of profiles and
micro-holes in diamond and quartz substrates with nanometer-scale
boundaries is shown. Experimental results of multilayer dielectric
cover treatment are also presented. Possibility of precise upper layer
(thickness of 70–140 nm) removal is demonstrated. Processes of thin
metal film (60 nm and 350 nm thick) treatment are considered.
Isolation tracks (conductance ~ 10-11 S) 1.6–2.5 μm in width in
conductive metal layers are formed.
Abstract: Mobile Ad Hoc network is an infrastructure less
network which operates with the coordination of each node. Each node
believes to help another node, by forwarding its data to/from another
node. Unlike a wired network, nodes in an ad hoc network are resource
(i.e. battery, bandwidth computational capability and so on)
constrained. Such dependability of one node to another and limited
resources of nodes can result in non cooperation by any node to
accumulate its resources. Such non cooperation is known as selfish
behavior.
This paper discusses the performance analysis of very well known
MANET single-path (i.e. AODV) and multi-path (i.e. AOMDV)
routing protocol, in the presence of selfish behaviors. Along with
existing selfish behaviors, a new variation is also studied. Extensive
simulations were carried out using ns-2 and the study concluded that
the multi-path protocol (i.e. AOMDV) with link disjoint configuration
outperforms the other two configurations.
Abstract: Multi-level voltage source inverters offer several
advantages such as; derivation of a refined output voltage with
reduced total harmonic distortion (THD), reduction of voltage ratings
of the power semiconductor switching devices and also the reduced
electro-magnetic-interference problems etc. In this paper, new
carrier-overlapped phase-disposition or sub-harmonic sinusoidal
pulse width modulation (CO-PD-SPWM) and also the carrieroverlapped
phase-disposition space vector modulation (CO-PDSVPWM)
schemes for a six-level diode-clamped inverter topology
are proposed. The principle of the proposed PWM schemes is similar
to the conventional PD-PWM with a little deviation from it in the
sense that the triangular carriers are all overlapped. The overlapping
of the triangular carriers on one hand results in an increased number
of switchings, on the other hand this facilitates an improved spectral
performance of the output voltage. It is demonstrated through
simulation studies that the six-level diode-clamped inverter with the
use of CO-PD-SPWM and CO-PD-SVPWM proposed in this paper is
capable of generating multiple levels in its output voltage. The
advantages of the proposed PWM schemes can be derived to benefit,
especially at lower modulation indices of the inverter and hence this
aspect of the proposed PWM schemes can be well exploited in high
power applications requiring low speeds of operation of the drive.
Abstract: The study investigates the mixing performance of
electrokinetically-driven power-law fluids in a microchannel
containing patterned trapezoid blocks. The effects of the geometry
parameters of the patterned trapezoid blocks and the flow behavior
index in the power-law model on the mixing efficiency within the
microchannel are explored. The results show that the mixing efficiency
can be improved by increasing the width of the blocks and extending
the length of upper surface of the blocks. In addition, the results show
that the mixing efficiency increases with an increasing flow behavior
index. Furthermore, it is shown that a heterogeneous patterning of the
zeta potential on the upper surfaces of the trapezoid blocks prompts
the formation of local flow recirculations, and therefore improves the
mixing efficiency. Consequently, it is shown that the mixing
performance improves with an increasing magnitude of the
heterogeneous surface zeta potential.
Abstract: In recent years Malaysia has included renewable
energy as an alternative fuel to help in diversifying the country-s
energy reliance on oil, natural gas, coal and hydropower with
biomass and solar energy gaining priority. The scope of this paper is
to look at the designing procedures and analysis of a solar thermal
parabolic trough concentrator by simulation utilizing meteorological
data in several parts of Malaysia. Parameters which include the
aperture area, the diameter of the receiver and the working fluid may
be varied to optimize the design. Aperture area is determined by
considering the width and the length of the concentrator whereas the
geometric concentration ratio (CR) is obtained by considering the
width and diameter of the receiver. Three types of working fluid are
investigated. Theoretically, concentration ratios can be very high in
the range of 10 to 40 000 depending on the optical elements used and
continuous tracking of the sun. However, a thorough analysis is
essential as discussed in this paper where optical precision and
thermal analysis must be carried out to evaluate the performance of
the parabolic trough concentrator as the theoretical CR is not the only
factor that should be considered.
Abstract: Induction motors are being used in greater numbers
throughout a wide variety of industrial and commercial applications
because it provides many benefits and reliable device to convert the
electrical energy into mechanical motion. In some application it-s
desired to control the speed of the induction motor. Because of the
physics of the induction motor the preferred method of controlling its
speed is to vary the frequency of the AC voltage driving the motor. In
recent years, with the microcontroller incorporated into an appliance
it becomes possible to use it to generate the variable frequency AC
voltage to control the speed of the induction motor.
This study investigates the microcontroller based variable
frequency power inverter. the microcontroller is provide the variable
frequency pulse width modulation (PWM) signal that control the
applied voltage on the gate drive, which is provides the required
PWM frequency with less harmonics at the output of the power
inverter.
The fully controlled bridge voltage source inverter has been
implemented with semiconductors power devices isolated gate
bipolar transistor (IGBT), and the PWM technique has been
employed in this inverter to supply the motor with AC voltage.
The proposed drive system for three & single phase power inverter
is simulated using Matlab/Simulink. The Matlab Simulation Results
for the proposed system were achieved with different SPWM. From
the result a stable variable frequency inverter over wide range has
been obtained and a good agreement has been found between the
simulation and hardware of a microcontroller based single phase
inverter.
Abstract: Although silicon photonic devices provide a significantly larger bandwidth and dissipate a substantially less power than the electronic devices, they suffer from a large size due to the fundamental diffraction limit and the weak optical response of Si. A potential solution is to exploit Si plasmonics, which may not only miniaturize the photonic device far beyond the diffraction limit, but also enhance the optical response in Si due to the electromagnetic field confinement. In this paper, we discuss and summarize the recently developed metal-insulator-Si-insulator-metal nanoplasmonic waveguide as well as various passive and active plasmonic components based on this waveguide, including coupler, bend, power splitter, ring resonator, MZI, modulator, detector, etc. All these plasmonic components are CMOS compatible and could be integrated with electronic and conventional dielectric photonic devices on the same SOI chip. More potential plasmonic devices as well as plasmonic nanocircuits with complex functionalities are also addressed.
Abstract: In this study, stress distributions on dental implants
made of functionally graded biomaterials (FGBM) are investigated
numerically. The implant body is considered to be subjected to axial
compression loads. Numerical problem is assumed to be 2D, and
ANSYS commercial software is used for the analysis. The cross
section of the implant thread varies as varying the height (H) and the
width (t) of the thread. According to thread dimensions of implant
and material properties of FGBM, equivalent stress distribution on
the implant is determined and presented with contour plots along
with the maximum equivalent stress values. As a result, with
increasing material gradient parameter (n), the equivalent stress
decreases, but the minimum stress distribution increases. Maximum
stress values decrease with decreasing implant radius (r). Maximum
von Mises stresses increases with decreasing H when t is constant.
On the other hand, the stress values are not affected by variation of t
in the case of H = constant.
Abstract: Many applications require surface modification and
micro-structuring of polymers. For these purposes is mainly used
ultraviolet (UV) radiation from excimer lamps or excimer lasers.
However, these sources have a decided disadvantage - degrading the
polymer deep inside due to relatively big radiation penetration depth
which may exceed 100 μm. In contrast, extreme ultraviolet (EUV)
radiation is absorbed in a layer approximately 100 nm thick only. In
this work, the radiation from a discharge-plasma EUV source (with
wavelength 46.9 nm) based on a capillary discharge driver is focused
with a spherical Si/Sc multilayer mirror for surface modification of
PMMA sample or thin gold layer (thickness about 40 nm). It was
found that the focused EUV laser beam is capable by one shot to
ablate PMMA or layer of gold, even if the focus is significantly
influenced by astigmatism.