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Wet Thermal Oxidation of Epitaxial
4H-SiC Substrate: An Experimental Process for
Device Fabrication
-- Sanjeev Kumar Gupta, Ameer Azam and
Jamil Akhtar
A thoroughly optimized wet thermal oxidation process of epitaxial 4H-SiC on both terminating faces has
been presented here. The optimum flow of molecular oxygen and inertial pressure inside the quartz horizontal
furnace have to be taken as the initial parameter during the whole oxidation process. Wafers are loaded in nitrogen
ambient to increase the mean free path for incoming oxidizing agent. The time of oxidation varies from
0.5 hours to 6 hours with 0.5 hours step time. Rate of oxidation on C-face has been found nearly 10 times
faster than on Si-face of 4H-SiC wafer. The oxide thickness has been measured by a variable angle ellipsometer and
the result has been verified by a surface profiler. A number of samples have been oxidized for each experiment in
order to generate the statistical data.
© 2009 IUP. All Rights Reserved.
A Novel Design of CMOS DO-CCII for Use in
Current-Mode Applications
-- Hassan J Motlak, Syed A Imam and
S Naseem Ahmad
In this paper, a novel Dual-Output second generation Current Conveyor (DO-CCII) circuit using
resistive compensation technique is proposed. The resistive compensation technique is a very simple and powerful
technique used to improve the bandwidth of CMOS DO-CCII without extra power consumption. P-spice simulations
for MIETEC 0.5 µm CMOS technology show that the current mode and voltage mode bandwidths are 2.3 GHz and
3.3 GHz respectively, with power consumption of 2 mW. The simulation results, which confirm the desired
results, have been included.
© 2009 IUP. All Rights Reserved
Role of Metaheuristics Optimization Approach in
Image Segmentation Techniques
-- Tilottama Goswami
Performance of real-world applications in computer vision and image understanding largely depend on the
efficiency of low level tasks involved. One of such low level tasks is the image segmentation process, which is from
the combinatorial optimization problem domain. The survey paper emphasizes the recent use and increasing growth
of the metaheuristics approach based on natural computing inspired by natural and biological systems for solving
the image segmentation specific to various domain-specific applications. The findings of recent studies of such
approximate algorithmic approach, largely based on heuristics, to obtain near-optimal solutions are showing strong evidence
to the fact that they can be applied to almost all approaches of various image segmentation techniques, such as
edge detection, region-oriented, morphological watersheds and clustering. The paper works towards bridging the
gap with regard to drawbacks of the state-of-the-art solution of the various segmentation techniques and the
available metaheuristic techniques and technologies like particle swarm optimization, Ant Colony Optimization (ACO)
and Genetic Algorithms (GA). Finally, it proposes modeling such automated system for learning algorithms based
on signals-to-symbol model.
© 2009 IUP. All Rights Reserved.
Credit Card Fraud Detection Using Artificial Neural Networks with a Rule-Based Component
-- Ogwueleka Francisca Nonyelum and
Inyiama Hyacinth Chibueze
Fraud detection involves identifying a fraud as quickly as possible once it has been perpetrated. It requires a tool
that is intelligent enough to adapt to criminals' strategies and ever-changing tactics to commit fraud. This paper
presents an automated credit card fraud (CCF) detection system based on neural network technology and rule-based
component. The Self-Organizing Map (SOM) algorithm was used to create a model of a typical cardholder's behavior
and analyze the features of transactions, thus detecting fraudulent transactions. An Artificial Neural Network
(ANN) trained with the unsupervised learning method was applied to the data to generate models. An approach
was developed to CCF detection that utilizes four clusters (instead of the usual two-stage model normally used in
fraud detection algorithms) to reduce the erroneous classification of legitimate transactions as fraudulent and to ensure
a more accurate result.
© 2009 IUP. All Rights Reserved.
Design of Bootlace Lens Beam Forming Network
of Three Input Ports
-- G S Tomar, Ravi Pratap Singh Kushwah and P K Singhal
In this paper, a modified geometry and design approach for equal height circular lens has been proposed. This
design will overcome the shortcomings of conventional design of Rotman lens, which has been in practice for decades.
The new design of equal height circular lens is the most appropriate choice for multiple beam forming due to its
reduced spillover features. The new design of Equal height circular lens at Ultra High Frequency (UHF) band has
been created and fabricated to justify the proposed design, and the results are encouraging, as it perfectly matches with
the theoretical evaluation.
© 2009 IUP. All Rights Reserved.
A Comparative Study of Compact Stacked
Rectangular Microstrip Antennas Using a Pair of T-Shaped Slots
-- Ravi M Yadahalli, Vani R M and P V Hunagund
In this paper, we present the size reduction of a Stacked Rectangular Microstrip Antenna (SRMSA) using a
co-axial probe feed. The size of the SRMSA is reduced by embedding a pair of T-slots either in the lower patch, upper
patch or on both patches. Using co-axial probe feed, 23.66% of compactness in the antenna size with a bandwidth
of 1.63% is obtained for the embedded T-slots in the lower patch of the SRMSA. This compactness is more than
that of the other compact SRMSA using T-slots in upper or on both patches of SRMSA. The parameter study is
carried out in all the three cases using IE3D simulation software by varying the slot length of the T-slots. Later
these simulation results are confirmed by verifying them with the experimental results.
© 2009 IUP. All Rights Reserved.
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