Hari, V S; Dr. Jagathy Raj, V P; Dr.Gopikakumari, R(Cochin University of Science And Technology, June , 2013)
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Abstract:
The basic concepts of digital signal processing are taught to the students
in engineering and science. The focus of the course is on linear,
time invariant systems. The question as to what happens when the
system is governed by a quadratic or cubic equation remains unanswered
in the vast majority of literature on signal processing. Light has
been shed on this problem when John V Mathews and Giovanni L Sicuranza
published the book Polynomial Signal Processing. This book
opened up an unseen vista of polynomial systems for signal and image
processing. The book presented the theory and implementations
of both adaptive and non-adaptive FIR and IIR quadratic systems
which offer improved performance than conventional linear systems.
The theory of quadratic systems presents a pristine and virgin area of
research that offers computationally intensive work. Once the area of
research is selected, the next issue is the choice of the software tool to
carry out the work. Conventional languages like C and C++ are easily
eliminated as they are not interpreted and lack good quality plotting
libraries. MATLAB is proved to be very slow and so do SCILAB and
Octave. The search for a language for scientific computing that was
as fast as C, but with a good quality plotting library, ended up in
Python, a distant relative of LISP. It proved to be ideal for scientific
computing. An account of the use of Python, its scientific computing
package scipy and the plotting library pylab is given in the appendix Initially, work is focused on designing predictors that exploit the polynomial
nonlinearities inherent in speech generation mechanisms. Soon,
the work got diverted into medical image processing which offered
more potential to exploit by the use of quadratic methods. The major
focus in this area is on quadratic edge detection methods for retinal
images and fingerprints as well as de-noising raw MRI signals
Description:
School of Engineering
Cochin University of Science and Technology
Zachariah,E J; Vasudevan, K; Pravinkumar,P A; Mohanan, P; K G Nair(Indian Journal of Radio & Space Physics, February , 1984)
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Abstract:
The design, erection and evalution procedures for it microwave anechuic chamber competed at Cochin University for
antenna studies are presented the chamber has an average reflectivity level of - 32 dB on at X-band frequencies, and it i,
comparable to international standards.
Thomas Lee, S; Dr.Nampoori,V P N; Dr. Radhakrishnan, P(Cochin University of Science & Technology, May , 2003)
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Abstract:
Advent of lasers together with the advancement in fiber optics technology has revolutionized the sensor technology. Advancement in the telemetric applications of optical fiber based measurements is an added bonus. The present thesis describes variety of fiber based sensors using techniques like micro bending, long period grating and evanescent waves. Sensors to measure various physical and chemical parameters are described in this thesis.
Description:
International School of Photonics,
Cochin University of Science and Technology
Geetha, K; Radhakrishnan, P(International School of Photonics, June , 2006)
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Abstract:
The rapid developments in fields such as fibre optic communication
engineering and integrated optical electronics have expanded the interest and
have increased the expectations about guided wave optics, in which optical
waveguides and optical fibres play a central role. The technology of guided
wave photonics now plays a role in generating information (guided-wave
sensors) and processing information (spectral analysis, analog-to-digital
conversion and other optical communication schemes) in addition to its
original application of transmitting information (fibre optic communication).
Passive and active polymer devices have generated much research
interest recently because of the versatility of the fabrication techniques and
the potential applications in two important areas – short distant
communication network and special functionality optical devices such as
amplifiers, switches and sensors. Polymer optical waveguides and fibres are
often designed to have large cores with 10-1000 micrometer diameter to
facilitate easy connection and splicing.
Large diameter polymer optical fibres being less fragile and vastly
easier to work with than glass fibres, are attractive in sensing applications.
Sensors using commercial plastic optical fibres are based on ideas already
used in silica glass sensors, but exploiting the flexible and cost effective
nature of the plastic optical fibre for harsh environments and throw-away
sensors.
In the field of Photonics, considerable attention is centering on the
use of polymer waveguides and fibres, as they have a great potential to create
all-optical devices. By attaching organic dyes to the polymer system we can
incorporate a variety of optical functions. Organic dye doped polymer
waveguides and fibres are potential candidates for solid state gain media.
High power and high gain optical amplification in organic dye-doped
polymer waveguide amplifier is possible due to extremely large emission
cross sections of dyes. Also, an extensive choice of organic dye dopants is
possible resulting in amplification covering a wide range in the visible region.
In this paper the design issues of compact genetic microstrip antennas for mobile
applications has been investigated. The antennas designed using Genetic Algorithms
(GA) have an arbitrary shape and occupies less area (compact) compared to the
traditionally designed antenna for the same frequency but with poor performance. An
attempt has been made to improve the performance of the genetic microstrip antenna by
optimizing the ground plane (GP) to have a fish bone like structure. The genetic antenna
with the GP optimized is even better compared to the traditional and the genetic antenna.
Description:
Antennas and Propagation Society International Symposium, 2008. AP-S 2008. IEEE
A compact microstrip multiband antenna on a
modified ground plane which can operate over the bands starting
from 900 MHz to 5.35 GHz which includes the GSM (880-960)
GPS (1568-1592 MHz), DCS (1710-1880 MHz), and PCS (1850-
1990 MHz). UMTS (1920-2170 MHz), IEEE 802.11 b/g (2400-
2484) and WLAN IEEE 802.11a band (5.15-5.35) is reported in
this paper. The overall dimension of the antenna is 33 x 33 mm2
including the top patch with a dimension 22 x 22 mm2. The
experimental results of the antenna are presented in this paper.
The results confirm that the antenna exhibits wide band
characteristics and covers 7 bands of operation
Jayaprakash, P; Dr. Menon, A K(Cochin University of Science And Technology, March 15, 1999)
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Abstract:
A GIS has been designed with limited Functionalities; but with a novel approach in
Aits design. The spatial data model adopted in the design of KBGIS is the unlinked
vector model. Each map entity is encoded separately in vector fonn, without referencing
any of its neighbouring entities. Spatial relations, in other words, are not encoded. This
approach is adequate for routine analysis of geographic data represented on a planar map,
and their display (Pages 105-106). Even though spatial relations are not encoded
explicitly, they can be extracted through the specially designed queries.
This work was undertaken as an experiment to study the feasibility of developing a
GIS using a knowledge base in place of a relational database. The source of input spatial
data was accurate sheet maps that were manually digitised. Each identifiable geographic
primitive was represented as a distinct object, with its spatial properties and attributes
defined. Composite spatial objects, made up of primitive objects, were formulated, based
on production rules defining such compositions. The facts and rules were then organised
into a production system, using OPS5
Description:
Department of Computer Science
School of Computer Science Studies
Cochin University of Science and Technology
Gopikrishna, M; Deepti Das, Krishna; Aanandan,C K; Mohanan, P; Vasudevan, K(Wiley InterScience, April , 2009)
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Abstract:
The design and performance of a stepped slot printed monopole antenna in the ultrawideband is presented in this article. Multiple resonances generated by the stepped slot geometry are matched in the ultrawideband using a modified microstrip feed. The impedance bandwidth (SWR < 2) of the antenna is from 3 to 11 GHz. Radiation patterns are stable and omnidirectional with appreciable gain throughout the band. Performance of the antenna is also analyzed in the time domain, which reveals good pulse handling capabilities. Compact geometry of the antenna allows easy commercial deployment.
Mridula, S; Anju, Pradeep; Mohanan, P(IEEE, August , 2011)
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Abstract:
Electric permittivity and magnetic permeability control electromagnetic wave propagation th rough materials. I n naturally
occu rring materials, these are positive. Artificial materials exhi b iting negative material properties have been reported :
they are referred to as metamaterials. This paper concentrates on a ring-type split-ring resonator (SRR) exhibiting
negative magnetic permeability. The design and synthesis of the SRR using the genetic-algorithm approach is explained
in detail. A user-friendly g raphical user i nterface (G U I ) for an SRR optim izer and estimator using MATLAB TM is also
presented
Description:
IEEE Antennas and Propagation Magazine, Vol. 53, No. 4, August 20 1 1
Mridula, S; Binu, Paul; Mythili, P; Mohanan, P(Wiley Subscription Services, Inc., A Wiley Company, December , 2010)
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Abstract:
A method for simultaneously enhancing the bandwidth
and reducing the size of microstrip antennas (MSAs) using a modified
ground plane (GP) has been proposed with design formulas. A combshaped
truncated GP is used for this purpose. This method provides an
overall compactness up to 85% for proximity-coupled MSAs in the
frequency range of 900 MHz–5.5 GHz with an improvement inbandwidth up to seven times when compared with the conventional ones
Description:
MICROWAVE AND OPTICAL TECHNOLOGY LETTERS / Vol. 52, No. 12, December 2010
Shynu, S V; Gijo,Augustin; Aanandan,C K; Mohanan, P; Vasudevan, K(Progress In Electromagnetics Research, 2006)
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Abstract:
The design of a compact, single feed, dual frequency
dual polarized and electronically reconfigurable microstrip antenna is
presented in this paper. A square patch loaded with a hexagonal slot
having extended slot arms constitutes the fundamental structure of
the antenna. The tuning of the two resonant frequencies is realized by
varying the effective electrical length of the slot arms by embedding
varactor diodes across the slots. A high tuning range of 34.43%
(1.037–1.394 GHz) and 9.27% (1.359–1.485 GHz) is achieved for the
two operating frequencies respectively, when the bias voltage is varied
from 0 to −30 V. The salient feature of this design is that it uses no
matching networks even though the resonant frequencies are tuned in
a wide range with good matching below −10 dB. The antenna has an
added advantage of size reduction up to 80.11% and 65.69% for the two
operating frequencies compared to conventional rectangular patches.
Prakash,P N; Dr.Ramaiah,D(National Institute for Interdisciplinary Science and Technology,CSIR, December , 2008)
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Abstract:
Development of organic molecules that exhibit selective
interactions with different biomolecules has immense significance
in biochemical and medicinal applications. In this context, our main
objective has been to design a few novel functionaIized molecules
that can selectively bind and recognize nucleotides and DNA in the aqueous medium through non-covalent interactions. Our strategy
was to design novel cycIophane receptor systems based on the
anthracene chromophore linked through different bridging moieties
and spacer groups. It was proposed that such systems would have a
rigid structure with well defined cavity, wherein the aromatic
chromophore can undergo pi-stacking interactions with the guest
molecules. The viologen and imidazolium moieties have been
chosen as bridging units, since such groups, can in principle, could
enhance the solubility of these derivatives in the aqueous medium
as well as stabilize the inclusion complexes through electrostatic
interactions.We synthesized a series of water soluble novel functionalized
cyclophanes and have investigated their interactions with
nucleotides, DNA and oligonucIeotides through photophysical.
chiroptical, electrochemical and NMR techniques. Results indicate
that these systems have favorable photophysical properties and
exhibit selective interactions with ATP, GTP and DNA involving
electrostatic. hydrophobic and pi-stacking interactions inside the
cavity and hence can have potential use as probes in biology.
Akhil, K Nair; Dr.Ramaiah,D(Cochin University Of Science And Technology, October 3, 2013)
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Abstract:
Design and study of molecular receptors capable of mimicking
natural processes has found applications in basic research as well as in
the development of potentially useful technologies. Of the various
receptors reported, the cyclophanes are known to encapsulate guest
molecules in their cavity utilizing various non–covalent interactions
resulting in significant changes in their optical properties. This unique
property of the cyclophanes has been widely exploited for the
development of selective and sensitive probes for a variety of guest
molecules including complex biomolecules. Further, the incorporation of
metal centres into these systems added new possibilities for designing
receptors such as the metallocyclophanes and transition metal
complexes, which can target a large variety of Lewis basic functional
groups that act as selective synthetic receptors.
The ligands that form complexes with the metal ions, and are
capable of further binding to Lewis-basic substrates through open
coordination sites present in various biomolecules are particularly
important as biomolecular receptors. In this context, we synthesized a
few anthracene and acridine based metal complexes and novel
metallocyclophanes and have investigated their photophysical and
biomolecular recognition properties.
Description:
Photosciences and Photonics
Chemical Sciences and Technology Division
CSIR-National Institute for Interdisciplinary Science and
Technology (CSIR-NIIST), Trivandrum