Abstract: A high-frequency low-power sinusoidal quadrature
oscillator is presented through the use of two 2nd-order low-pass
current-mirror (CM)-based filters, a 1st-order CM low-pass filter and
a CM bilinear transfer function. The technique is relatively simple
based on (i) inherent time constants of current mirrors, i.e. the
internal capacitances and the transconductance of a diode-connected
NMOS, (ii) a simple negative resistance RN formed by a resistor load
RL of a current mirror. Neither external capacitances nor inductances
are required. As a particular example, a 1.9-GHz, 0.45-mW, 2-V
CMOS low-pass-filter-based all-current-mirror sinusoidal quadrature
oscillator is demonstrated. The oscillation frequency (f0) is 1.9 GHz
and is current-tunable over a range of 370 MHz or 21.6 %. The
power consumption is at approximately 0.45 mW. The amplitude
matching and the quadrature phase matching are better than 0.05 dB
and 0.15°, respectively. Total harmonic distortions (THD) are less
than 0.3 %. At 2 MHz offset from the 1.9 GHz, the carrier to noise
ratio (CNR) is 90.01 dBc/Hz whilst the figure of merit called a
normalized carrier-to-noise ratio (CNRnorm) is 153.03 dBc/Hz. The
ratio of the oscillation frequency (f0) to the unity-gain frequency (fT)
of a transistor is 0.25. Comparisons to other approaches are also
included.
Abstract: In this paper a neural adaptive control method has
been developed and applied to robot control. Simulation results are
presented to verify the effectiveness of the controller. These results
show that the performance by using this controller is better than
those which just use either direct inverse control or predictive
control. In addition, they show that the resulting is a useful method
which combines the advantages of both direct inverse control and
predictive control.
Abstract: The most important parameter in transformers life
expectancy is the hot-spot temperature level which accelerates the
rate of aging of the insulation. The aim of this paper is to present
thermal models for transformers loaded at prefabricated MV/LV
transformer substations and outdoor situations. The hot-spot
temperature of transformers is studied using their top-oil temperature
rise models. The thermal models proposed for hot-spot and top-oil
temperatures of different operating situations are compared. Since the
thermal transfer is different for indoor and outdoor transformers
considering their operating conditions, their hot-spot thermal models
differ from each other. The proposed thermal models are verified by
the results obtained from the experiments carried out on a typical
1600 kVA, 30 /0.4 kV, ONAN transformer for both indoor and
outdoor situations.
Abstract: This paper presents a new method of analog fault diagnosis based on back-propagation neural networks (BPNNs) using wavelet decomposition and fractal dimension as preprocessors. The proposed method has the capability to detect and identify faulty components in an analog electronic circuit with tolerance by analyzing its impulse response. Using wavelet decomposition to preprocess the impulse response drastically de-noises the inputs to the neural network. The second preprocessing by fractal dimension can extract unique features, which are the fed to a neural network as inputs for further classification. A comparison of our work with [1] and [6], which also employs back-propagation (BP) neural networks, reveals that our system requires a much smaller network and performs significantly better in fault diagnosis of analog circuits due to our proposed preprocessing techniques.
Abstract: Median filter is widely used to remove impulse noise
without blurring sharp edges. However, when noise level increased,
or with thin edges, median filter may work poorly. This paper
proposes a new filter, which will detect edges along four possible
directions, and then replace noise corrupted pixel with estimated
noise-free edge median value. Simulations show that the proposed
multi-stage directional median filter can provide excellent
performance of suppressing impulse noise in all situations.
Abstract: In this paper, we study a class of serially concatenated block codes (SCBC) based on matrix interleavers, to be employed in fixed wireless communication systems. The performances of SCBC¬coded systems are investigated under various interleaver dimensions. Numerical results reveal that the matrix interleaver could be a competitive candidate over conventional block interleaver for frame lengths of 200 bits; hence, the SCBC coding based on matrix interleaver is a promising technique to be employed for speech transmission applications in many international standards such as pan-European Global System for Mobile communications (GSM), Digital Cellular Systems (DCS) 1800, and Joint Detection Code Division Multiple Access (JD-CDMA) mobile radio systems, where the speech frame contains around 200 bits.
Abstract: This paper proposed a novel model for short term load
forecast (STLF) in the electricity market. The prior electricity
demand data are treated as time series. The model is composed of
several neural networks whose data are processed using a wavelet
technique. The model is created in the form of a simulation program
written with MATLAB. The load data are treated as time series data.
They are decomposed into several wavelet coefficient series using
the wavelet transform technique known as Non-decimated Wavelet
Transform (NWT). The reason for using this technique is the belief
in the possibility of extracting hidden patterns from the time series
data. The wavelet coefficient series are used to train the neural
networks (NNs) and used as the inputs to the NNs for electricity load
prediction. The Scale Conjugate Gradient (SCG) algorithm is used as
the learning algorithm for the NNs. To get the final forecast data, the
outputs from the NNs are recombined using the same wavelet
technique. The model was evaluated with the electricity load data of
Electronic Engineering Department in Mandalay Technological
University in Myanmar. The simulation results showed that the
model was capable of producing a reasonable forecasting accuracy in
STLF.
Abstract: Performance of millimeter-wave (mm-wave) multiband
orthogonal frequency division multiplexing (MB-OFDM) ultrawideband
(UWB) signal generation using frequency quadrupling
technique and transmission over fiber is experimentally investigated.
The frequency quadrupling is achived by using only one Mach-
Zehnder modulator (MZM) that is biased at maximum transmission
(MATB) point. At the output, a frequency quadrupling signal is
obtained then sent to a second MZM. This MZM is used for MBOFDM
UWB signal modulation. In this work, we demonstrate 30-
GHz mm-wave wireless that carries three-bands OFDM UWB
signals, and error vector magnitude (EVM) is used to analyze the
transmission quality. It is found that our proposed technique leads to
an improvement of 3.5 dB in EVM at 40% of local oscillator (LO)
modulation with comparison to the technique using two cascaded
MZMs biased at minimum transmission (MITB) point.
Abstract: This paper presents the design related to the
electronic system design of the respiratory signal, including phases
for processing, followed by the transmission and reception of this
signal and finally display. The processing of this signal is added to
the ECG and temperature sign, put up last year. Under this scheme is
proposed that in future also be conditioned blood pressure signal
under the same final printed circuit and worked.
Abstract: A bond graph model of a hydroelectric plant is
proposed. In order to analyze the system some structural properties
of a bond graph are used. The structural controllability of
the hydroelctric plant is described. Also, the steady state of the
state variables applying the bond graph in a derivative causality
assignment is obtained. Finally, simulation results of the system
are shown.
Abstract: Color constancy algorithms are generally based on the
simplified assumption about the spectral distribution or the reflection
attributes of the scene surface. However, in reality, these assumptions
are too restrictive. The methodology is proposed to extend existing
algorithm to applying color constancy locally to image patches rather
than globally to the entire images.
In this paper, a method based on low-level image features using
superpixels is proposed. Superpixel segmentation partition an image
into regions that are approximately uniform in size and shape. Instead
of using entire pixel set for estimating the illuminant, only superpixels
with the most valuable information are used. Based on large scale
experiments on real-world scenes, it can be derived that the estimation
is more accurate using superpixels than when using the entire image.
Abstract: A new digital transceiver circuit for asynchronous frame detection is proposed where both the transmitter and receiver contain all digital components, thereby avoiding possible use of conventional devices like monostable multivibrators with unstable external components such as resistances and capacitances. The proposed receiver circuit, in particular, uses a combinational logic block yielding an output which changes its state as soon as the start bit of a new frame is detected. This, in turn, helps in generating an efficient receiver sampling clock. A data latching circuit is also used in the receiver to latch the recovered data bits in any new frame. The proposed receiver structure is also extended from 4- bit information to any general n data bits within a frame with a common expression for the output of the combinational logic block. Performance of the proposed hardware design is evaluated in terms of time delay, reliability and robustness in comparison with the standard schemes using monostable multivibrators. It is observed from hardware implementation that the proposed circuit achieves almost 33 percent speed up over any conventional circuit.
Abstract: Distributed Generation (DG) in the form of renewable
power generation systems is currently preferred for clean power
generation. It has a significant impact on the distribution systems.
This impact may be either positively or negatively depending on the
distribution system, distributed generator and load characteristics. In
this works, an overview of DG is briefly introduced. The technology
of DG is also listed while the technical impacts and economic
impacts are explained.
Abstract: Artificial Neural Network (ANN) has been
extensively used for classification of heart sounds for its
discriminative training ability and easy implementation. However, it
suffers from overparameterization if the number of nodes is not
chosen properly. In such cases, when the dataset has redundancy
within it, ANN is trained along with this redundant information that
results in poor validation. Also a larger network means more
computational expense resulting more hardware and time related
cost. Therefore, an optimum design of neural network is needed
towards real-time detection of pathological patterns, if any from heart
sound signal. The aims of this work are to (i) select a set of input
features that are effective for identification of heart sound signals and
(ii) make certain optimum selection of nodes in the hidden layer for a
more effective ANN structure. Here, we present an optimization
technique that involves Singular Value Decomposition (SVD) and
QR factorization with column pivoting (QRcp) methodology to
optimize empirically chosen over-parameterized ANN structure.
Input nodes present in ANN structure is optimized by SVD followed
by QRcp while only SVD is required to prune undesirable hidden
nodes. The result is presented for classifying 12 common
pathological cases and normal heart sound.
Abstract: A wireless Ad-hoc network consists of wireless nodes
communicating without the need for a centralized administration, in
which all nodes potentially contribute to the routing process.In this
paper, we report the simulation results of four different scenarios for
wireless ad hoc networks having thirty nodes. The performances of
proposed networks are evaluated in terms of number of hops per
route, delay and throughput with the help of OPNET simulator.
Channel speed 1 Mbps and simulation time 600 sim-seconds were
taken for all scenarios. For the above analysis DSR routing protocols
has been used. The throughput obtained from the above analysis
(four scenario) are compared as shown in Figure 3. The average
media access delay at node_20 for two routes and at node_20 for four
different scenario are compared as shown in Figures 4 and 5. It is
observed that the throughput will degrade when it will follow
different hops for same source to destination (i.e. it has dropped from
1.55 Mbps to 1.43 Mbps which is around 9.7%, and then dropped to
0.48Mbps which is around 35%).
Abstract: In this paper, we propose a chaotic cipher system consisting of Improved Volterra Filters and the mapping that is created from the actual voice by using Radial Basis Function Network. In order to achieve a practical system, the system supposes to use the digital communication line, such as the Internet, to maintain the parameter matching between the transmitter and receiver sides. Therefore, in order to withstand the attack from outside, it is necessary that complicate the internal state and improve the sensitivity coefficient. In this paper, we validate the robustness of proposed method from three perspectives of "Chaotic properties", "Randomness", "Coefficient sensitivity".
Abstract: In this paper, a modified CCCII is presented. We have used a current mirror with low supply voltage. This circuit is operated at low supply voltage of ±1V. Tspice simulations for TSMC 0.18μm CMOS Technology has shown that the current and voltage bandwidth are respectively 3.34GHz and 4.37GHz, and parasitic resistance at port X has a value of 169.320 for a control current of 120μA. In order to realize this circuit, we have implemented in this first step a universal current mode filter where the frequency can reach the 134.58MHz. In the second step, we have implemented two simulated inductors: one floating and the other grounded. These two inductors are operated in high frequency and variable depending on bias current I0. Finally, we have used the two last inductors respectively to implement two sinusoidal oscillators domains of frequencies respectively: [470MHz, 692MHz], and [358MHz, 572MHz] for bias currents I0 [80μA, 350μA].
Abstract: This paper proposes a feed-forward control in a halfbridge
resonant dc link inverter. The configuration of feed-forward
control is based on synchronous sigma-delta modulation and the halfbridge
resonant dc link inverter consists of two inductors, one
capacitor and two power switches. The simulation results show the
proposed technique can reject non-ideal dc bus improving the total
harmonic distortion.
Abstract: In this paper, hybrid FDMA-TDMA access technique in a cooperative distributive fashion introducing and implementing a modified protocol introduced in [1] is analyzed termed as Power and Cooperation Diversity Gain Protocol (PCDGP). A wireless network consists of two users terminal , two relays and a destination terminal equipped with two antennas. The relays are operating in amplify-and-forward (AF) mode with a fixed gain. Two operating modes: cooperation-gain mode and powergain mode are exploited from source terminals to relays, as it is working in a best channel selection scheme. Vertical BLAST (Bell Laboratories Layered Space Time) or V-BLAST with minimum mean square error (MMSE) nulling is used at the relays to perfectly detect the joint signals from multiple source terminals. The performance is analyzed using binary phase shift keying (BPSK) modulation scheme and investigated over independent and identical (i.i.d) Rayleigh, Ricean-K and Nakagami-m fading environments. Subsequently, simulation results show that the proposed scheme can provide better signal quality of uplink users in a cooperative communication system using hybrid FDMATDMA technique.
Abstract: Fast delay estimation methods, as opposed to
simulation techniques, are needed for incremental performance
driven layout synthesis. On-chip inductive effects are becoming
predominant in deep submicron interconnects due to increasing clock
speed and circuit complexity. Inductance causes noise in signal
waveforms, which can adversely affect the performance of the circuit
and signal integrity. Several approaches have been put forward which
consider the inductance for on-chip interconnect modelling. But for
even much higher frequency, of the order of few GHz, the shunt
dielectric lossy component has become comparable to that of other
electrical parameters for high speed VLSI design. In order to cope up
with this effect, on-chip interconnect has to be modelled as
distributed RLCG line. Elmore delay based methods, although
efficient, cannot accurately estimate the delay for RLCG interconnect
line. In this paper, an accurate analytical delay model has been
derived, based on first and second moments of RLCG
interconnection lines. The proposed model considers both the effect
of inductance and conductance matrices. We have performed the
simulation in 0.18μm technology node and an error of as low as less
as 5% has been achieved with the proposed model when compared to
SPICE. The importance of the conductance matrices in interconnect
modelling has also been discussed and it is shown that if G is
neglected for interconnect line modelling, then it will result an delay
error of as high as 6% when compared to SPICE.