Abstract: In this paper, a target signal detection method using
multiple signal classification (MUSIC) algorithm is proposed. The
MUSIC algorithm is a subspace-based direction of arrival (DOA)
estimation method. The algorithm detects the DOAs of multiple
sources using the inverse of the eigenvalue-weighted eigen spectra. To
apply the algorithm to target signal detection for GSC-based
beamforming, we utilize its spectral response for the target DOA in
noisy conditions. For evaluation of the algorithm, the performance of
the proposed target signal detection method is compared with that of
the normalized cross-correlation (NCC), the fixed beamforming, and
the power ratio method. Experimental results show that the proposed
algorithm significantly outperforms the conventional ones in receiver
operating characteristics(ROC) curves.
Abstract: This article proposes a current-mode square-rooting
circuit using current follower transconductance amplifier (CTFA).
The amplitude of the output current can be electronically controlled
via input bias current with wide input dynamic range. The proposed
circuit consists of only single CFTA. Without any matching
conditions and external passive elements, the circuit is then
appropriate for an IC architecture. The magnitude of the output signal
is temperature-insensitive. The PSpice simulation results are
depicted, and the given results agree well with the theoretical
anticipation. The power consumption is approximately 1.96mW at
±1.5V supply voltages.
Abstract: In this paper, a block code to minimize the peak-toaverage
power ratio (PAPR) of orthogonal frequency division
multiplexing (OFDM) signals is proposed. It is shown that cyclic
shift and codeword inversion cause not change to peak envelope
power. The encoding rule for the proposed code comprises of
searching for a seed codeword, shifting the register elements, and
determining codeword inversion, eliminating the look-up table for
one-to-one correspondence between the source and the coded data.
Simulation results show that OFDM systems with the proposed code
always have the minimum PAPR.
Abstract: A fast settling multipath CMOS OTA for high speed
switched capacitor applications is presented here. With the basic
topology similar to folded-cascode, bandwidth and DC gain of the
OTA are enhanced by adding extra paths for signal from input to
output. Designed circuit is simulated with HSPICE using level 49
parameters (BSIM 3v3) in 0.35mm standard CMOS technology. DC
gain achieved is 56.7dB and Unity Gain Bandwidth (UGB) obtained
is 1.15GHz. These results confirm that adding extra paths for signal
can improve DC gain and UGB of folded-cascode significantly.
Abstract: The ability to predict an accurate temperature
distribution requires the knowledge of the losses, the thermal
characteristics of the materials, and the cooling conditions, all of
which are very difficult to quantify. In this paper, the impact of the
effects of iron and copper losses are investigated separately and
their effects on the heating in various points of the stator of an
induction motor, is highlighted by using two simple tests. In addition,
the effect of a defect, such as an open circuit in a phase of the stator,
on the heating is also obtained by a no-load test.
The squirrel cage induction motor is rated at 2.2 kW; 380 V; 5.2
A; Δ connected; 50 Hz; 1420 rpm and the class of insulation F, has
been thermally tested under several load conditions. Several
thermocouples were placed in strategic points of the stator.
Abstract: A higher order spline interpolated contour obtained
with up-sampling of homogenously distributed coordinates for
segmentation of kidney region in different classes of ultrasound
kidney images has been developed and presented in this paper. The
performance of the proposed method is measured and compared with
modified snake model contour, Markov random field contour and
expert outlined contour. The validation of the method is made in
correspondence with expert outlined contour using maximum coordinate
distance, Hausdorff distance and mean radial distance
metrics. The results obtained reveal that proposed scheme provides
optimum contour that agrees well with expert outlined contour.
Moreover this technique helps to preserve the pixels-of-interest
which in specific defines the functional characteristic of kidney. This
explores various possibilities in implementing computer-aided
diagnosis system exclusively for US kidney images.
Abstract: This paper describes a low-power second-order filter
for a continuous-time chopper stabilized capacitive sensor interface,
integrated with a fully differential post-CMOS surface-micromachined
MEMS pressure sensor. The circuit uses a single-ended
folded-cascode operational amplifier and two GM-C filters connected
in cascade. The circuit is realized in a 0.18 μm CMOS process and
offers differential to single-ended conversion. The novelty of the
scheme is the cascade of two GM-C filters to achieve a second-order
filter while minimizing power dissipation. The simulated filter cutoff
frequency is 1.14 kHz at common-mode voltage 1.65 V,
operating from a 3.3 V supply while dissipating 172μW of power.
The filter achieves an operating range of 1V for an output load of
1MOhm and 10pF.
Abstract: With a development of Hybrid Electric Vehicle(HEV),
A photovoltaic(PV) generation system is used for charging batteries in many cases. A dc/dc converter using PV power for a battery charger
requires a high efficiency. In this paper, A ZVS boost converter using the renewable energies for HEV charger is proposed. Through the theoretical analysis and experimental result, operation modes and characteristics of the proposed topology are verified.
Abstract: The 4G front-end transceiver needs a high
performance which can be obtained mainly with an optimal
architecture and a multi-band Local Oscillator. In this study, we
proposed and presented a new architecture of multi-band frequency
synthesizer based on an Inverse Sine Phase Detector Phase Locked
Loop (ISPD PLL) without any filters and any controlled gain block
and associated with adapted multi band LC tuned VCO using a
several numeric controlled capacitive branches but not binary
weighted. The proposed architecture, based on 0.35μm CMOS
process technology, supporting Multi-band GSM/DCS/DECT/
UMTS/WiMax application and gives a good performances: a phase
noise @1MHz -127dBc and a Factor Of Merit (FOM) @ 1MHz -
186dB and a wide band frequency range (from 0.83GHz to 3.5GHz),
that make the proposed architecture amenable for monolithic
integration and 4G multi-band application.
Abstract: In this work, a characterization and modeling of
packet loss of a Voice over Internet Protocol (VoIP) communication
is developed. The distributions of the number of consecutive received
and lost packets (namely gap and burst) are modeled from the
transition probabilities of two-state and four-state model.
Measurements show that both models describe adequately the burst
distribution, but the decay of gap distribution for non-homogeneous
losses is better fit by the four-state model. The respective
probabilities of transition between states for each model were
estimated with a proposed algorithm from a set of monitored VoIP
calls in order to obtain representative minimum, maximum and
average values for both models.
Abstract: In this paper an alternative analysis in the time
domain is described and the results of the interpolation process are
presented by means of functions that are based on the rule of
conditional mathematical expectation and the covariance function. A
comparison between the interpolation error caused by low order
filters and the classic sinc(t) truncated function is also presented.
When fewer samples are used, low-order filters have less error. If the
number of samples increases, the sinc(t) type functions are a better
alternative. Generally speaking there is an optimal filter for each
input signal which depends on the filter length and covariance
function of the signal. A novel scheme of work for adaptive
interpolation filters is also presented.
Abstract: In this paper, we consider the analysis of the
acquisition process for a hybrid double-dwell system with antenna
diversity for DS-CDMA (direct sequence-code division multiple
access) using an adaptive threshold. Acquisition systems with a fixed
threshold value are unable to adapt to fast varying mobile
communications environments and may result in a high false alarm
rate, and/or low detection probability. Therefore, we propose an
adaptively varying threshold scheme through the use of a cellaveraging
constant false alarm rate (CA-CFAR) algorithm, which is
well known in the field of radar detection. We derive exact
expressions for the probabilities of detection and false alarm in
Rayleigh fading channels. The mean acquisition time of the system
under consideration is also derived. The performance of the system is
analyzed and compared to that of a hybrid single dwell system.
Abstract: In this paper three basic approaches and different
methods under each of them for extracting region of interest (ROI)
from stationary images are explored. The results obtained for each of
the proposed methods are shown, and it is demonstrated where each
method outperforms the other. Two main problems in ROI
extraction: the channel selection problem and the saliency reversal
problem are discussed and how best these two are addressed by
various methods is also seen. The basic approaches are 1) Saliency
based approach 2) Wavelet based approach 3) Clustering based
approach. The saliency approach performs well on images containing
objects of high saturation and brightness. The wavelet based
approach performs well on natural scene images that contain regions
of distinct textures. The mean shift clustering approach partitions the
image into regions according to the density distribution of pixel
intensities. The experimental results of various methodologies show
that each technique performs at different acceptable levels for
various types of images.
Abstract: This paper presents an analysis on the capacity and performance of MIMO-OFDM systems. The work is focused on the capacity of MIMO-OFDM systems over rician fading channel, in the case of the channel being known at the receiver only, which is more practical case of the channel. Simple expression for capacity is derived for the case of correlated rician fading. The performance of some MIMO-OFDM implementations with rician fading model is presented using an Alamouti coding scheme and Simulation results are obtained for both capacity and performance analysis.
Abstract: We discuss the signal detection through nonlinear
threshold systems. The detection performance is assessed by the
probability of error Per . We establish that: (1) when the signal is
complete suprathreshold, noise always degrades the signal detection
both in the single threshold system and in the parallel array of
threshold devices. (2) When the signal is a little subthreshold, noise
degrades signal detection in the single threshold system. But in the
parallel array, noise can improve signal detection, i.e., stochastic
resonance (SR) exists in the array. (3) When the signal is predominant
subthreshold, noise always can improve signal detection and SR
always exists not only in the single threshold system but also in the
parallel array. (4) Array can improve signal detection by raising the
number of threshold devices. These results extend further the
applicability of SR in signal detection.
Abstract: WiMAX is defined as Worldwide Interoperability for
Microwave Access by the WiMAX Forum, formed in June 2001 to
promote conformance and interoperability of the IEEE 802.16
standard, officially known as WirelessMAN. The attractive features
of WiMAX technology are very high throughput and Broadband
Wireless Access over a long distance. A detailed simulation
environment is demonstrated with the UGS, nrtPS and ertPS service
classes for throughput, delay and packet delivery ratio for a mixed
environment of fixed and mobile WiMAX. A simple mobility aspect
is considered for the mobile WiMAX and the PMP mode of
transmission is considered in TDD mode. The Network Simulator 2
(NS-2) is the tool which is used to simulate the WiMAX network
scenario. A simple Priority Scheduler and Weighted Round Robin
Schedulers are the WiMAX schedulers used in the research work
Abstract: We integrate TiN/Ni/HfO2/Si RRAM cell with a
vertical gate-all-around (GAA) nanowire transistor to achieve
compact 4F2 footprint in a 1T1R configuration. The tip of the Si
nanowire (source of the transistor) serves as bottom electrode of the
memory cell. Fabricated devices with nanowire diameter ~ 50nm
demonstrate ultra-low current/power switching; unipolar switching
with 10μA/30μW SET and 20μA/30μW RESET and bipolar switching
with 20nA/85nW SET and 0.2nA/0.7nW RESET. Further, the
switching current is found to scale with nanowire diameter making the
architecture promising for future scaling.
Abstract: This paper proposes a method which reduces power consumption in single-error correcting, double error-detecting checker circuits that perform memory error correction code. Power is minimized with little or no impact on area and delay, using the degrees of freedom in selecting the parity check matrix of the error correcting codes. The genetic algorithm is employed to solve the non linear power optimization problem. The method is applied to two commonly used SEC-DED codes: standard Hamming and odd column weight Hsiao codes. Experiments were performed to show the performance of the proposed method.
Abstract: This paper discusses the implementation of the Kalman
Filter along with the Global Positioning System (GPS) for indoor
robot navigation. Two dimensional coordinates is used for the map
building, and refers to the global coordinate which is attached to the
reference landmark for position and direction information the robot
gets. The Discrete Kalman Filter is used to estimate the robot position,
project the estimated current state ahead in time through time update
and adjust the projected estimated state by an actual measurement at
that time via the measurement update. The navigation test has been
performed and has been found to be robust.
Abstract: This paper addresses control of commutation of switched reluctance (SR) motor without the use of a physical position detector. Rotor position detection schemes for SR motor based on magnetisation characteristics of the motor use normal excitation or applied current /voltage pulses. The resulting schemes are referred to as passive or active methods respectively. The research effort is in realizing an economical sensorless SR rotor position detector that is accurate, reliable and robust to suit a particular application. An effective and reliable means of generating commutation signals of an SR motor based on inductance profile of its stator windings determined using active probing technique is presented. The scheme has been validated online using a 4-phase 8/6 SR motor and an 8-bit processor.