Circular antenna array has gained immense
popularity in the field of communications nowadays. It has
proved to be a better alternative over other types of antenna
array configuration due to its all-azimuth scan capability,
and a beam pattern which can be kept invariant. This paper is
basically concerned with the thinning of a large multiple
concentric circular ring arrays of uniformly excited isotropic
antennas based on Improved Particle Swarm Optimization
(IPSO) method. In this paper a 9 ringed Concentric Circular
Antenna Array (CCAA) with central element feeding is
considered. The computational results show that the number
of antenna array elements can be brought down from 279 to
147 with simultaneous reduction in Side Lobe Level of about
20 dB with a fixed half power beamwidth.
Application of Bio-Inspired Optimization Technique for Finding the Optimal se...IDES Editor
In this paper the maximum sidelobe level (SLL) reductions
of three-ring concentric circular antenna arrays
(CCAA) without and with central element feeding are examined
using two different classes of evolutionary optimization
techniques to finally determine the global optimal three-ring
CCAA design. Apart from physical construction of a CCAA,
one may broadly classify its design into two major categories:
uniformly excited arrays and non-uniformly excited arrays.
The present paper assumes non-uniform excitations and uniform
spacing of excitation elements in each three-ring CCAA
design and a design goal of maximizing SLL reduction associated
with optimal beam patterns and beam widths. The design
problem is modeled as an optimization problem for each CCAA
design. Binary coded Genetic Algorithm (BGA) and Bacteria
Foraging Optimization (BFO) are used to determine an optimum
set of normalized excitation weights for CCAA elements,
which, when incorporated, results in a radiation pattern with
optimal (maximum) SLL reduction. Among the various CCAA
designs the three-ring CCAA containing (N1=4, N2=6, N3=8)
elements along with central element feeding proves to be global
optimal design. BFO yields global minimum SLL (-34.18
dB) and global minimum BWFN (81.50) for the optimal design.
Printed UWB Circular and Modified Circular Disc Monopole AntennasIDES Editor
The document summarizes the simulation of two types of printed ultra-wideband (UWB) monopole antennas: circular and modified circular disk monopole antennas. The circular disk antenna operated from 2.1 to 12.4 GHz while the modified circular antenna operated from 2.3 to 11.3 GHz. Both antennas had omnidirectional radiation patterns, with the E-plane patterns becoming distorted at higher frequencies. The gap between the patch and ground plane was a crucial parameter for achieving broad bandwidth. The modified circular antenna had slightly higher efficiency but a reduced bandwidth compared to the circular disk antenna.
Dual Band to Wideband Pentagon-shaped Patch Antenna with Frequency Reconfigur...IJECEIAES
A dual band to wideband reconfigurable pentagon-shaped antenna with EBG unit cell is proposed. A minimal number of two EBG unit cell is deployed to realize frequency reconfigurable mechanism. By varying the state of the EBG the antenna is capable to change its dual band operation to wideband alternately. There are three cases that have been analysed, first case is the EBG incorporated antenna with ideal and second is with the active EBG. Subsequently, the third cases is the fabricated ideal EBG incorporated antenna. The dual band operation is at 1.8 GHz and 5.2 GHz while the wide band from 1.6 GHz to 2.37 GHz (770 MHz). The proposed reconfigurable antenna is suitable to be implemented for LTE (1.6 GHz), Wi-Fi (5.2 GHz), WiMAX (2.3 GHz) and cognitive radio application.
Polarisation non-reciprocity cancelling in Sagnac fibre ring interferometer: ...Kurbatov Roman
This document summarizes a study on reducing polarization non-reciprocity (PNR) in Sagnac fibre ring interferometers (FRIs) to extremely low levels. The study models all practical defects in FRIs to simulate their effects on PNR. It finds that using several meters of an input polarizing lightguide can suppress PNR to below 10-10 deg/h, meeting the criteria for "PNR cancelling". This is surprising given the lightguide's own imperfections limit its polarization extinction ratio to only 40-60 dB. The complete FRI configuration is considered, including an imperfect fibre coupler, and additional PNR components are identified.
ESS-Bilbao Initiative Workshop. RF structure comparison for low energy accele...ESS BILBAO
This document compares different radio frequency (RF) structures that can be used for particle acceleration in the low energy range of 3 MeV to 200 MeV. It discusses figures of merit like shunt impedance and beam dynamics constraints for different structure types, including drift tube linacs (DTLs), coupled cavity drift tube linacs (CCDTLs), separated drift tube linacs (SDTLs), spoke cavities, and traveling wave structures. A comparison performed by the HIPPI collaboration assessed the performance of these structures based on factors like shunt impedance, beam dynamics acceptance, and mechanical complexity. Overall, no consensus structure exists for the low energy range, and the optimal design depends on project-specific parameters and future technology developments.
Double feedback technique for reduction of Noise LNA with gain enhancementijceronline
In this paper we present a balun low noise amplifier (LNA) in which the gain is boosted by using a double feedback structure. The circuit is based on a conventional balun LNA with noise and distortion cancelation. The LNA is based on the combination of a common-gate (CG) stage and common-source (CS) stage. We propose to replace the load resistors by active loads, which can be used to implement local feedback loops (in the CG and CS stages). This will boost the gain and reduce the noise figure (NF). Simulation results, with a 130nm CMOS technology, show that the gain is 24dB and the NF is less than 2.7dB. The total power dissipation is only 5.4mW (since no extra blocks are required), leading to a figure-of-merit (FOM) of 3.8mW-1 using a nominal 1.2V supply. Measurement results are presented for the proposed DFBLNA included in a receiver frontend for biomedical applications (ISM and WMTS).
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Application of Bio-Inspired Optimization Technique for Finding the Optimal se...IDES Editor
In this paper the maximum sidelobe level (SLL) reductions
of three-ring concentric circular antenna arrays
(CCAA) without and with central element feeding are examined
using two different classes of evolutionary optimization
techniques to finally determine the global optimal three-ring
CCAA design. Apart from physical construction of a CCAA,
one may broadly classify its design into two major categories:
uniformly excited arrays and non-uniformly excited arrays.
The present paper assumes non-uniform excitations and uniform
spacing of excitation elements in each three-ring CCAA
design and a design goal of maximizing SLL reduction associated
with optimal beam patterns and beam widths. The design
problem is modeled as an optimization problem for each CCAA
design. Binary coded Genetic Algorithm (BGA) and Bacteria
Foraging Optimization (BFO) are used to determine an optimum
set of normalized excitation weights for CCAA elements,
which, when incorporated, results in a radiation pattern with
optimal (maximum) SLL reduction. Among the various CCAA
designs the three-ring CCAA containing (N1=4, N2=6, N3=8)
elements along with central element feeding proves to be global
optimal design. BFO yields global minimum SLL (-34.18
dB) and global minimum BWFN (81.50) for the optimal design.
Printed UWB Circular and Modified Circular Disc Monopole AntennasIDES Editor
The document summarizes the simulation of two types of printed ultra-wideband (UWB) monopole antennas: circular and modified circular disk monopole antennas. The circular disk antenna operated from 2.1 to 12.4 GHz while the modified circular antenna operated from 2.3 to 11.3 GHz. Both antennas had omnidirectional radiation patterns, with the E-plane patterns becoming distorted at higher frequencies. The gap between the patch and ground plane was a crucial parameter for achieving broad bandwidth. The modified circular antenna had slightly higher efficiency but a reduced bandwidth compared to the circular disk antenna.
Dual Band to Wideband Pentagon-shaped Patch Antenna with Frequency Reconfigur...IJECEIAES
A dual band to wideband reconfigurable pentagon-shaped antenna with EBG unit cell is proposed. A minimal number of two EBG unit cell is deployed to realize frequency reconfigurable mechanism. By varying the state of the EBG the antenna is capable to change its dual band operation to wideband alternately. There are three cases that have been analysed, first case is the EBG incorporated antenna with ideal and second is with the active EBG. Subsequently, the third cases is the fabricated ideal EBG incorporated antenna. The dual band operation is at 1.8 GHz and 5.2 GHz while the wide band from 1.6 GHz to 2.37 GHz (770 MHz). The proposed reconfigurable antenna is suitable to be implemented for LTE (1.6 GHz), Wi-Fi (5.2 GHz), WiMAX (2.3 GHz) and cognitive radio application.
Polarisation non-reciprocity cancelling in Sagnac fibre ring interferometer: ...Kurbatov Roman
This document summarizes a study on reducing polarization non-reciprocity (PNR) in Sagnac fibre ring interferometers (FRIs) to extremely low levels. The study models all practical defects in FRIs to simulate their effects on PNR. It finds that using several meters of an input polarizing lightguide can suppress PNR to below 10-10 deg/h, meeting the criteria for "PNR cancelling". This is surprising given the lightguide's own imperfections limit its polarization extinction ratio to only 40-60 dB. The complete FRI configuration is considered, including an imperfect fibre coupler, and additional PNR components are identified.
ESS-Bilbao Initiative Workshop. RF structure comparison for low energy accele...ESS BILBAO
This document compares different radio frequency (RF) structures that can be used for particle acceleration in the low energy range of 3 MeV to 200 MeV. It discusses figures of merit like shunt impedance and beam dynamics constraints for different structure types, including drift tube linacs (DTLs), coupled cavity drift tube linacs (CCDTLs), separated drift tube linacs (SDTLs), spoke cavities, and traveling wave structures. A comparison performed by the HIPPI collaboration assessed the performance of these structures based on factors like shunt impedance, beam dynamics acceptance, and mechanical complexity. Overall, no consensus structure exists for the low energy range, and the optimal design depends on project-specific parameters and future technology developments.
Double feedback technique for reduction of Noise LNA with gain enhancementijceronline
In this paper we present a balun low noise amplifier (LNA) in which the gain is boosted by using a double feedback structure. The circuit is based on a conventional balun LNA with noise and distortion cancelation. The LNA is based on the combination of a common-gate (CG) stage and common-source (CS) stage. We propose to replace the load resistors by active loads, which can be used to implement local feedback loops (in the CG and CS stages). This will boost the gain and reduce the noise figure (NF). Simulation results, with a 130nm CMOS technology, show that the gain is 24dB and the NF is less than 2.7dB. The total power dissipation is only 5.4mW (since no extra blocks are required), leading to a figure-of-merit (FOM) of 3.8mW-1 using a nominal 1.2V supply. Measurement results are presented for the proposed DFBLNA included in a receiver frontend for biomedical applications (ISM and WMTS).
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
The document discusses optical coupling between light sources and optical fibers. It defines coupling efficiency as the ratio of power coupled into the fiber to power emitted from the source. Radiance and radiation patterns of different light sources are described. Expressions are provided for calculating the power coupled from a source to a fiber based on the source and fiber parameters. Methods to improve coupling efficiency such as lensing are also discussed. The document also covers topics like fiber-to-fiber coupling loss, mechanical misalignment loss, and fiber end defects.
Eliminating polarisation nonreciprocity of small size sagnac fibre ring inter...Kurbatov Roman
This document discusses reducing polarisation nonreciprocity (PNR) in small Sagnac fibre ring interferometers (FRIs) used in fibre optic gyroscopes (FOGs). It presents an analytical model for how PNR scales exponentially with the length of the input polarising lightguide. Unlike previous models, this shows that by making the lightguide sufficiently long, the required polarisation extinction ratio can be made arbitrarily small, improving FOG accuracy for applications requiring high precision. It also describes a numerical simulation approach to model PNR in FRIs considering the specific properties and interactions of components like the polarised light, proton-exchanged waveguides, fibre coil, and splices between optical axes.
Macro-Bending Loss of Single-Mode Fiber beyond Its Operating WavelengthTELKOMNIKA JOURNAL
A standard telecommunication-grade single-mode optical fiber is designed to have a
low macro-bending loss in its entire operating wavelengths to comply with the ITU-T
Recommendation G.652. In this paper, we described the potential use of such a fiber as an
intensity-based sensor due to the macro-bending loss as an alternative to using a bendingsensitive
fiber. We calculated the macro-bending loss of several single-mode optical fiber
patchcords using the classical Marcuse equation at several wavelengths, and measured its
transmission loss due to bending using an optical spectrum analyzer. For each type of fibers
there is a wavelength with a significant macro-bending loss of the LP11 mode when the Vnumber
of the fiber lies between 2.4 and 4, and that of the LP01 mode when the V-number of the
fiber lies between 1 and 2.4. This work shows a thorough mathematical and experimental
analysis for the posibility in using standard telecommunication fibers for intensity based-fiber
sensor taking the benefit of bending loss phenomenon using commercial light sources.
Research Inventy : International Journal of Engineering and Science is publis...researchinventy
This document summarizes the design and development of a switchable fractal patch antenna for GPS applications. The antenna uses a stacked fractal patch design to reduce size and mitigate interference. Two fractal patch antennas with different radiation patterns are stacked and selected using diode switching. Simulation results show the stacked fractal patch antenna achieves a return loss of -29.01 dB, VSWR of 1.30, and size reduction of up to 62.4% compared to a basic patch antenna design through the use of fractal iterations. The stacked fractal patch design provides a compact antenna that can directly replace existing antennas for GPS applications.
The document describes using transmission electron microscopy (TEM) and energy-filtered transmission electron microscopy (EFTEM) to characterize nanofiber bundles detected as defects in a semiconductor fabrication facility (FAB). A dual-beam focused ion beam was used to prepare a TEM cross-section sample of one of the fiber bundles. EFTEM elemental mapping revealed that the fibers are composed of silicon oxide and originate from a nickel particle, which likely broke the underlying silicon oxide-silicon nitride-silicon oxide layers during processing, providing a pathway for oxygen diffusion and fiber growth. The technique allows pinpointing the source of defects to minimize downtime in the FAB.
Fiber Bragg gratings are filters built into the core of optical fibers that reflect specific wavelengths of light and transmit others. They can be used as inline filters or wavelength-specific reflectors to improve optical signal quality. The document discusses several types of FBGs: uniform FBGs with consistent grating periods; chirped FBGs with varying periods that act as dispersion compensators; blazed FBGs with tilted grating planes that reflect light out of the fiber; phase-shifted FBGs with periodic index changes that create narrow transmission windows; and long-period FBGs that couple light into cladding modes, removing resonant wavelengths from the system. Each FBG type has distinct features and applications in optical communications, sensing, and laser
An optical modulator is a device that modulates or varies the amplitude of an optical signal in a controlled manner. It generates desired intensity and color in light by changing optical parameters like transmission, refractive index, or reflection according to an input signal. Common types of optical modulators include electroabsorption modulators, electro-optic modulators, acousto-optic modulators, and Mach-Zehnder interferometric modulators. Optical modulators are important for applications like optical communication systems.
A Study on Uniform and Apodized Fiber Bragg GratingsIJSRD
This document summarizes a study on modeling uniform and apodized fiber Bragg gratings (FBGs) using MATLAB. The authors simulate different FBG designs and analyze their reflection spectra and side lobe strengths. Uniform FBGs are affected by changes in grating length, refractive index modulation, and pitch. Increasing length increases reflectivity but decreases bandwidth, while increasing index modulation increases reflectivity and bandwidth. Apodized FBGs using Gaussian, sinc, and raised cosine profiles reduce side lobes compared to uniform FBGs, at the cost of lower reflectivity. Apodized FBGs are preferred over uniform FBGs when wavelength selectivity is important.
Optimization of Uniform Fiber Bragg Grating Reflection Spectra for Maximum Re...ijceronline
The document discusses optimizing the reflection spectra of uniform fiber Bragg gratings (FBGs) for maximum reflectivity and narrow bandwidth. It analyzes how the grating length and refractive index modulation affect the reflectivity and spectral bandwidth using coupled mode theory. The simulations show that reflectivity increases with longer grating length or higher refractive index modulation, up to a maximum value, while bandwidth decreases with longer length but increases with higher modulation. Changing the refractive index profile shape does not impact the spectral response.
Power Efficiency Improvement in CE-OFDM System With 0 dB IBO for Transmission...CSCJournals
Orthogonal frequency division multiplexing (OFDM) OFDM has been adopted for high speed data transmission of multimedia traffic such as HomePlug A/V and Mobile WiMax. However, OFDM also has a drawback of a high PAPR (peak-to-average-power-ratio). Due to this high PAPR amplifier usually does not act in dynamic range. One potential solution for reducing the peak-to-average power ratio (PAPR) in an OFDM system is to utilize a constant envelope OFDM (CE-OFDM) system. Furthermore, by utilizing continuous phase modulation (CPM) in a CE-OFDM system, the PAPR can be effectively reduced to 0 dB, allowing for the signal to be amplified with a power efficient non-linear power amplifier with Input Back-Off (IBO) of 0 dB. This paper describes a CE-OFDM based modem for Power Line Communications (PLC) over the low voltage distribution network. Relying on a preliminary characterization of a PLC network, a complete description of the modem is given. Also CE-OFDM is compared with conventional OFDM under HomePlug 1.0 in the presence of power amplifier nonlinearities, considering different values of IBO.
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
This document presents research on using directional versus omni-directional antennas for ultra-wideband (UWB) imaging applications in breast cancer detection. A modified directional patch antenna was designed and tested. Experiments using the directional antenna showed similar but slightly less accurate tumor location detection compared to omni-directional antennas, but maintained a 100% tumor existence detection rate. The directional antenna was more compact and simpler than omni-directional antennas for this application.
Extended electrical tuning of quantum cascade lasers with digitalSepehrAzureSky
In this report, the sampled grating distributed feedback laser architecture is modified with digital
concatenated gratings to partially compensate for the wavelength dependence of optical gain in a
standard high efficiency quantum cascade laser core. This allows equalization of laser threshold
over a wide wavelength range and demonstration of wide electrical tuning. With only two
control currents, a full tuning range of 500 nm (236 cm1
) has been demonstrated. Emission is
single mode, with a side mode suppression of >20 dB. V C 2013 AIP Publishing LLC.
[http://dx.doi.org/10.1063/1.4841635]
DESIGN AND ANALYSIS OF COMPACT UWB BAND PASS FILTERijeljournal
This paper presents design, implementation and analysis of an ultra-wideband (UWB) band-pass-filter using parallel-coupled microstrip line with defective ground plane and a uniform multi-mode resonator. The structure of the filter is designed on microwave substrate GML 1000 of dielectric constant 3.2 and height is 0.762 mm. Simulation is carried out by CST MSW software and optimized structure is fabricated. The frequency response is measured on vector analyzer and measured results show close approximation with simulation results. In this article modeling of the proposed filter is also reported. The electric model of the filter is analyzed by circuit theory and MATLAB. This model is validated by comparing the results with the CST simulation and VNA measured results. This filter is compact in size of dimension 30˟1.87 mm2 may be useful for modern wireless application of communication.
The document discusses potential future directions for few-mode fiber transmission. It describes how two-mode fiber can transmit in either the LP01 or two degenerate LP11 modes, providing 3 times the bandwidth of single-mode fiber. Challenges for few-mode fiber systems include complex optical and electronic design as well as mode coupling issues. The document advocates starting with two-mode fiber to demonstrate the concept before moving to higher-order few-mode fibers.
SIDE LOBE REDUCTION OF CIRCULAR ARRAY USING TAYLOR DISTRIBUTION FUNCTION IN ...IAEME Publication
The VHF/UHF band radar that using circular array antennas is a novel kind of radar, whose performances, such as angular accuracy, angular resolution, anti-jamming and low-altitude coverage capabilities are better than the conventional VHF/UHF band radar. On one hand, we focus on how the directivity of array element will influence upon the array pattern. The performance characteristics of the single microstrip patch antenna can be further enhanced by using microstrip patch antenna array. On the other hand, in order to lower the side lobe level (SLL) of circular array antennas , we investigate the effectiveness of amplitude-weighted methods including Taylor Window and Gaussian Window.
Design of c slotted microstrip antenna using artificial neural network modeleSAT Journals
Abstract In this paper, neural network model has been used to estimation of resonance frequency of a coaxial feed C-slotted Microstrip Antenna. The Multi-Layer Perceptron Feed forward back Propagation (MLPFFBP) and Radial basis function Artificial Neural Network (RBFANN) have been used to implement the neural network model. A relative performance analysis of the proposed neural network for different training algorithms. Number of neurons and number of hidden layer is also carried out for estimating the resonance frequency. The method of moment (MOM) based IE3D software was used to generate data dictionary for training and validation set of ANN. The results obtain using ANN are compared with simulation feeding and found quite satisfactory and also it is concluded that RBFANN network is more accurate and fast compared to MLPFFBP network algorithm. Index Terms: Artificial Neural Network, C slot, Microstrip Antenna, Multilayer Feed Forward Networks, Radial basis function Artificial Neural Network, Resonance frequency.
This document provides information about light propagation through optical fibers. It begins by defining an optical fiber as a cylindrical waveguide made of glass that uses total internal reflection to transmit light. It then discusses the fiber's core and cladding layers and the conditions needed for total internal reflection. The key points covered include:
- Light propagation is guided through the fiber core by total internal reflection at the core-cladding interface.
- Only rays entering the fiber core within the acceptance angle will continue propagating through total internal reflection.
- Electromagnetic mode theory is needed to fully understand light propagation in fibers. Discrete modes exist that are solutions to Maxwell's equations.
- The evanescent field that penetrates the cl
The study of semiconductor layer effect on underground cables with Time Domai...IOSR Journals
This document presents a study on how the semiconductor layers in underground cables can affect Time Domain Reflectometry (TDR) measurements. The researchers developed a circuit model that includes the electrical resistance of the semiconductor layers to better simulate TDR signals. Simulations using the proposed model showed good agreement with measurements from a new cable but not an aged cable. The model was updated to represent resistance in the aged cable's semiconductor layers caused by degradation over time. Simulations with this updated model matched experimental TDR results from the aged cable better than the original model. The study demonstrates that changes in semiconductor layer resistance due to aging can impact TDR pulse propagation in cables.
This document describes the design of embedded-grating n+-i-n+ traveling-wave photodetectors (TWPDs). TWPDs can overcome bandwidth limitations by matching the optical group velocity to the electrical phase velocity. However, achieving perfect velocity matching is difficult. The proposed design embeds a grating within the waveguide core to tune the optical group velocity as needed. The grating acts as a dispersive medium that allows controlling the group velocity by optimizing grating parameters. Solving the coupled-mode equations describing field propagation within the structured waveguide allows determining the transfer matrix and analyzing the effect of the grating on the optical group velocity.
Particle Swarm Optimization with Constriction Factor and Inertia Weight Appro...IDES Editor
In this paper, an evolutionary optimization
technique, Particle Swarm Optimization with Constriction
Factor and Inertia Weight Approach (PSOCFIWA) is adopted
for the complex synthesis of three-ring Concentric Circular
Antenna Arrays (CCAA) with non-isotropic elements and
without and with central element feeding. It is shown that by
selection of a fitness function which controls more than one
parameter of the array pattern, and also by proper setting of
weight factors in fitness function, one can achieve very good
results. For each optimal design, optimal current excitation
weights and optimal radii are determined having the objective
of maximum Sidelobe Level (SLL) reduction. The extensive
computational results show that the CCAA designs having
central element feeding with non-isotropic elements yield
much more reduction in SLL as compared to the same not
having central element feeding. Moreover, the particular
CCAA containing 4, 6 and 8 number of elements in three
successive rings along with central element feeding yields
grand minimum SLL (-46.4 dB). Standard Particle Swarm
Optimization (PSO) is adopted to compare the results of the
PSOCFIWA algorithm.
Linear Antenna Array synthesis with Decreasing Sidelobe and Narrow BeamwidthIDES Editor
Synthesizing arrays with low sidelobe and pencil
beam radiation profile is under investigation for decades. A
variety of array structures are available, but the simplest and
useful structure is that of a linear array. Here, two basic
symmetric Linear Antenna Array structures are assumed. The
required array structure is assumed to provide low sidelobe
and pencil beam profile. Departure from a uniformity in
current and location profile has shown quiet appreciable
improvement in the radiation pattern. The simulations are
carried out using Differential Evolution Algorithm employing
Best of Random mutation strategy (DEBoR).
The document discusses optical coupling between light sources and optical fibers. It defines coupling efficiency as the ratio of power coupled into the fiber to power emitted from the source. Radiance and radiation patterns of different light sources are described. Expressions are provided for calculating the power coupled from a source to a fiber based on the source and fiber parameters. Methods to improve coupling efficiency such as lensing are also discussed. The document also covers topics like fiber-to-fiber coupling loss, mechanical misalignment loss, and fiber end defects.
Eliminating polarisation nonreciprocity of small size sagnac fibre ring inter...Kurbatov Roman
This document discusses reducing polarisation nonreciprocity (PNR) in small Sagnac fibre ring interferometers (FRIs) used in fibre optic gyroscopes (FOGs). It presents an analytical model for how PNR scales exponentially with the length of the input polarising lightguide. Unlike previous models, this shows that by making the lightguide sufficiently long, the required polarisation extinction ratio can be made arbitrarily small, improving FOG accuracy for applications requiring high precision. It also describes a numerical simulation approach to model PNR in FRIs considering the specific properties and interactions of components like the polarised light, proton-exchanged waveguides, fibre coil, and splices between optical axes.
Macro-Bending Loss of Single-Mode Fiber beyond Its Operating WavelengthTELKOMNIKA JOURNAL
A standard telecommunication-grade single-mode optical fiber is designed to have a
low macro-bending loss in its entire operating wavelengths to comply with the ITU-T
Recommendation G.652. In this paper, we described the potential use of such a fiber as an
intensity-based sensor due to the macro-bending loss as an alternative to using a bendingsensitive
fiber. We calculated the macro-bending loss of several single-mode optical fiber
patchcords using the classical Marcuse equation at several wavelengths, and measured its
transmission loss due to bending using an optical spectrum analyzer. For each type of fibers
there is a wavelength with a significant macro-bending loss of the LP11 mode when the Vnumber
of the fiber lies between 2.4 and 4, and that of the LP01 mode when the V-number of the
fiber lies between 1 and 2.4. This work shows a thorough mathematical and experimental
analysis for the posibility in using standard telecommunication fibers for intensity based-fiber
sensor taking the benefit of bending loss phenomenon using commercial light sources.
Research Inventy : International Journal of Engineering and Science is publis...researchinventy
This document summarizes the design and development of a switchable fractal patch antenna for GPS applications. The antenna uses a stacked fractal patch design to reduce size and mitigate interference. Two fractal patch antennas with different radiation patterns are stacked and selected using diode switching. Simulation results show the stacked fractal patch antenna achieves a return loss of -29.01 dB, VSWR of 1.30, and size reduction of up to 62.4% compared to a basic patch antenna design through the use of fractal iterations. The stacked fractal patch design provides a compact antenna that can directly replace existing antennas for GPS applications.
The document describes using transmission electron microscopy (TEM) and energy-filtered transmission electron microscopy (EFTEM) to characterize nanofiber bundles detected as defects in a semiconductor fabrication facility (FAB). A dual-beam focused ion beam was used to prepare a TEM cross-section sample of one of the fiber bundles. EFTEM elemental mapping revealed that the fibers are composed of silicon oxide and originate from a nickel particle, which likely broke the underlying silicon oxide-silicon nitride-silicon oxide layers during processing, providing a pathway for oxygen diffusion and fiber growth. The technique allows pinpointing the source of defects to minimize downtime in the FAB.
Fiber Bragg gratings are filters built into the core of optical fibers that reflect specific wavelengths of light and transmit others. They can be used as inline filters or wavelength-specific reflectors to improve optical signal quality. The document discusses several types of FBGs: uniform FBGs with consistent grating periods; chirped FBGs with varying periods that act as dispersion compensators; blazed FBGs with tilted grating planes that reflect light out of the fiber; phase-shifted FBGs with periodic index changes that create narrow transmission windows; and long-period FBGs that couple light into cladding modes, removing resonant wavelengths from the system. Each FBG type has distinct features and applications in optical communications, sensing, and laser
An optical modulator is a device that modulates or varies the amplitude of an optical signal in a controlled manner. It generates desired intensity and color in light by changing optical parameters like transmission, refractive index, or reflection according to an input signal. Common types of optical modulators include electroabsorption modulators, electro-optic modulators, acousto-optic modulators, and Mach-Zehnder interferometric modulators. Optical modulators are important for applications like optical communication systems.
A Study on Uniform and Apodized Fiber Bragg GratingsIJSRD
This document summarizes a study on modeling uniform and apodized fiber Bragg gratings (FBGs) using MATLAB. The authors simulate different FBG designs and analyze their reflection spectra and side lobe strengths. Uniform FBGs are affected by changes in grating length, refractive index modulation, and pitch. Increasing length increases reflectivity but decreases bandwidth, while increasing index modulation increases reflectivity and bandwidth. Apodized FBGs using Gaussian, sinc, and raised cosine profiles reduce side lobes compared to uniform FBGs, at the cost of lower reflectivity. Apodized FBGs are preferred over uniform FBGs when wavelength selectivity is important.
Optimization of Uniform Fiber Bragg Grating Reflection Spectra for Maximum Re...ijceronline
The document discusses optimizing the reflection spectra of uniform fiber Bragg gratings (FBGs) for maximum reflectivity and narrow bandwidth. It analyzes how the grating length and refractive index modulation affect the reflectivity and spectral bandwidth using coupled mode theory. The simulations show that reflectivity increases with longer grating length or higher refractive index modulation, up to a maximum value, while bandwidth decreases with longer length but increases with higher modulation. Changing the refractive index profile shape does not impact the spectral response.
Power Efficiency Improvement in CE-OFDM System With 0 dB IBO for Transmission...CSCJournals
Orthogonal frequency division multiplexing (OFDM) OFDM has been adopted for high speed data transmission of multimedia traffic such as HomePlug A/V and Mobile WiMax. However, OFDM also has a drawback of a high PAPR (peak-to-average-power-ratio). Due to this high PAPR amplifier usually does not act in dynamic range. One potential solution for reducing the peak-to-average power ratio (PAPR) in an OFDM system is to utilize a constant envelope OFDM (CE-OFDM) system. Furthermore, by utilizing continuous phase modulation (CPM) in a CE-OFDM system, the PAPR can be effectively reduced to 0 dB, allowing for the signal to be amplified with a power efficient non-linear power amplifier with Input Back-Off (IBO) of 0 dB. This paper describes a CE-OFDM based modem for Power Line Communications (PLC) over the low voltage distribution network. Relying on a preliminary characterization of a PLC network, a complete description of the modem is given. Also CE-OFDM is compared with conventional OFDM under HomePlug 1.0 in the presence of power amplifier nonlinearities, considering different values of IBO.
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
This document presents research on using directional versus omni-directional antennas for ultra-wideband (UWB) imaging applications in breast cancer detection. A modified directional patch antenna was designed and tested. Experiments using the directional antenna showed similar but slightly less accurate tumor location detection compared to omni-directional antennas, but maintained a 100% tumor existence detection rate. The directional antenna was more compact and simpler than omni-directional antennas for this application.
Extended electrical tuning of quantum cascade lasers with digitalSepehrAzureSky
In this report, the sampled grating distributed feedback laser architecture is modified with digital
concatenated gratings to partially compensate for the wavelength dependence of optical gain in a
standard high efficiency quantum cascade laser core. This allows equalization of laser threshold
over a wide wavelength range and demonstration of wide electrical tuning. With only two
control currents, a full tuning range of 500 nm (236 cm1
) has been demonstrated. Emission is
single mode, with a side mode suppression of >20 dB. V C 2013 AIP Publishing LLC.
[http://dx.doi.org/10.1063/1.4841635]
DESIGN AND ANALYSIS OF COMPACT UWB BAND PASS FILTERijeljournal
This paper presents design, implementation and analysis of an ultra-wideband (UWB) band-pass-filter using parallel-coupled microstrip line with defective ground plane and a uniform multi-mode resonator. The structure of the filter is designed on microwave substrate GML 1000 of dielectric constant 3.2 and height is 0.762 mm. Simulation is carried out by CST MSW software and optimized structure is fabricated. The frequency response is measured on vector analyzer and measured results show close approximation with simulation results. In this article modeling of the proposed filter is also reported. The electric model of the filter is analyzed by circuit theory and MATLAB. This model is validated by comparing the results with the CST simulation and VNA measured results. This filter is compact in size of dimension 30˟1.87 mm2 may be useful for modern wireless application of communication.
The document discusses potential future directions for few-mode fiber transmission. It describes how two-mode fiber can transmit in either the LP01 or two degenerate LP11 modes, providing 3 times the bandwidth of single-mode fiber. Challenges for few-mode fiber systems include complex optical and electronic design as well as mode coupling issues. The document advocates starting with two-mode fiber to demonstrate the concept before moving to higher-order few-mode fibers.
SIDE LOBE REDUCTION OF CIRCULAR ARRAY USING TAYLOR DISTRIBUTION FUNCTION IN ...IAEME Publication
The VHF/UHF band radar that using circular array antennas is a novel kind of radar, whose performances, such as angular accuracy, angular resolution, anti-jamming and low-altitude coverage capabilities are better than the conventional VHF/UHF band radar. On one hand, we focus on how the directivity of array element will influence upon the array pattern. The performance characteristics of the single microstrip patch antenna can be further enhanced by using microstrip patch antenna array. On the other hand, in order to lower the side lobe level (SLL) of circular array antennas , we investigate the effectiveness of amplitude-weighted methods including Taylor Window and Gaussian Window.
Design of c slotted microstrip antenna using artificial neural network modeleSAT Journals
Abstract In this paper, neural network model has been used to estimation of resonance frequency of a coaxial feed C-slotted Microstrip Antenna. The Multi-Layer Perceptron Feed forward back Propagation (MLPFFBP) and Radial basis function Artificial Neural Network (RBFANN) have been used to implement the neural network model. A relative performance analysis of the proposed neural network for different training algorithms. Number of neurons and number of hidden layer is also carried out for estimating the resonance frequency. The method of moment (MOM) based IE3D software was used to generate data dictionary for training and validation set of ANN. The results obtain using ANN are compared with simulation feeding and found quite satisfactory and also it is concluded that RBFANN network is more accurate and fast compared to MLPFFBP network algorithm. Index Terms: Artificial Neural Network, C slot, Microstrip Antenna, Multilayer Feed Forward Networks, Radial basis function Artificial Neural Network, Resonance frequency.
This document provides information about light propagation through optical fibers. It begins by defining an optical fiber as a cylindrical waveguide made of glass that uses total internal reflection to transmit light. It then discusses the fiber's core and cladding layers and the conditions needed for total internal reflection. The key points covered include:
- Light propagation is guided through the fiber core by total internal reflection at the core-cladding interface.
- Only rays entering the fiber core within the acceptance angle will continue propagating through total internal reflection.
- Electromagnetic mode theory is needed to fully understand light propagation in fibers. Discrete modes exist that are solutions to Maxwell's equations.
- The evanescent field that penetrates the cl
The study of semiconductor layer effect on underground cables with Time Domai...IOSR Journals
This document presents a study on how the semiconductor layers in underground cables can affect Time Domain Reflectometry (TDR) measurements. The researchers developed a circuit model that includes the electrical resistance of the semiconductor layers to better simulate TDR signals. Simulations using the proposed model showed good agreement with measurements from a new cable but not an aged cable. The model was updated to represent resistance in the aged cable's semiconductor layers caused by degradation over time. Simulations with this updated model matched experimental TDR results from the aged cable better than the original model. The study demonstrates that changes in semiconductor layer resistance due to aging can impact TDR pulse propagation in cables.
This document describes the design of embedded-grating n+-i-n+ traveling-wave photodetectors (TWPDs). TWPDs can overcome bandwidth limitations by matching the optical group velocity to the electrical phase velocity. However, achieving perfect velocity matching is difficult. The proposed design embeds a grating within the waveguide core to tune the optical group velocity as needed. The grating acts as a dispersive medium that allows controlling the group velocity by optimizing grating parameters. Solving the coupled-mode equations describing field propagation within the structured waveguide allows determining the transfer matrix and analyzing the effect of the grating on the optical group velocity.
Particle Swarm Optimization with Constriction Factor and Inertia Weight Appro...IDES Editor
In this paper, an evolutionary optimization
technique, Particle Swarm Optimization with Constriction
Factor and Inertia Weight Approach (PSOCFIWA) is adopted
for the complex synthesis of three-ring Concentric Circular
Antenna Arrays (CCAA) with non-isotropic elements and
without and with central element feeding. It is shown that by
selection of a fitness function which controls more than one
parameter of the array pattern, and also by proper setting of
weight factors in fitness function, one can achieve very good
results. For each optimal design, optimal current excitation
weights and optimal radii are determined having the objective
of maximum Sidelobe Level (SLL) reduction. The extensive
computational results show that the CCAA designs having
central element feeding with non-isotropic elements yield
much more reduction in SLL as compared to the same not
having central element feeding. Moreover, the particular
CCAA containing 4, 6 and 8 number of elements in three
successive rings along with central element feeding yields
grand minimum SLL (-46.4 dB). Standard Particle Swarm
Optimization (PSO) is adopted to compare the results of the
PSOCFIWA algorithm.
Linear Antenna Array synthesis with Decreasing Sidelobe and Narrow BeamwidthIDES Editor
Synthesizing arrays with low sidelobe and pencil
beam radiation profile is under investigation for decades. A
variety of array structures are available, but the simplest and
useful structure is that of a linear array. Here, two basic
symmetric Linear Antenna Array structures are assumed. The
required array structure is assumed to provide low sidelobe
and pencil beam profile. Departure from a uniformity in
current and location profile has shown quiet appreciable
improvement in the radiation pattern. The simulations are
carried out using Differential Evolution Algorithm employing
Best of Random mutation strategy (DEBoR).
For high performance communication systems, Side Lobe Level (SLL) reduction and improved directivity are the goal of antenna designers. In the recent years, many optimization techniques of antenna design are occupying demanding place over the analytical techniques. Though they have contributed attractive solutions, it is often obvious to select one that meets the particular design need at hand. In this paper, an optimization technique called Self-adaptive Differential Evolution (SaDE) that can be able to learn and behave intelligently along with hyper beam forming is integrated to determine an optimal set of excitation weights in the design of EcAA. Non-uniform excitation weights of the individual array elements of EcAA are performed to obtain reduced SLL, high directivity and flexible radiation pattern. To evaluate the improved performance of the proposed SaDE optimized hyper beam, comparison are done with uniformly excited, SaDE without hyper beam and Genetic Algorithm (GA). In general, the proposed work of pattern synthesis has resulted in much better reduction of SLL and FNBW than both the uniformly excited and thinned EcAA. The results of this study clearly reveal that the SLL highly reduced at a very directive beamwidth.
This document summarizes research on different techniques for miniaturizing antennas for wireless applications. It discusses using slots in microstrip patch antennas, high permittivity dielectric substrates, and magneto-dielectric substrates. Simulation results show that magneto-dielectric substrates provide the best miniaturization while maintaining good bandwidth and radiation efficiency compared to other techniques. The document concludes that magneto-dielectric materials present opportunities for designing small, high-performance antennas.
This document describes the design and implementation of an integrated ultrawideband (UWB)/reconfigurable-slot antenna for cognitive radio applications. A slot resonator is embedded in a disc monopole radiator to achieve a narrowband antenna, and a varactor diode is inserted across the slot to provide frequency reconfiguration between 5-6 GHz. Simulation and measurement results show the antenna achieves UWB performance from 3-11 GHz as well as tunable narrowband operation across the targeted range. Isolation between the UWB and narrowband functions is better than 16 dB across most of the operating bands.
DUAL BAND F-ANTENNA FOR EUROPE AND NORTH AMERICAijwmn
A single antenna for multiple bands are always beneficial from the design point of view. Here a single antenna which is fundamentally inverted F antenna is used, the uniqueness of the design is that , it uses trap technique to produce dual resonance from a single inverted F antenna . The trap used to block the current due to some frequencies and passes the current contributed by other frequencies. So in short , this trap is like a RF filter which has some passband as well as stop band. This trap approach uses a LC network to achieve this design goal .The two bands of interest are 865-870 MHz and 902-928 MHz .. The challenge of this design is that the frequency separation of the two bands is very small. In this case, and also the extra section for low frequency band is too small. Then, the influence of trap LC component variation due to tolerance to the two resonant frequencies is big, and so it is difficult to achieve good in band return loss within the LC tolerance. This is the main difficulty of this design. This issue is resolved by placing the low band section away from the end of the antenna. The antenna is designed on FR4 substrate material having thickness of 1.6 mm and hence it is a low cost solution which could use in various commercial applications which follows these bands.
Comparison between Rectangular and Circular Patch Antennas Arrayijceronline
In this paper, several designs of micorstip arrays antennas, suitable for wireless communication applications, are presented. This paper demonstratesseveral shapesof microstrip array antennas, such as rectangular and circular patch antennas array. Specifically, 4x1, 2x1, and single element of both shapes are designed and simulated bya full wave simulator(IE3d). Moreover, this paper presents acomparison between both rectangular and circular antenna arrays.Since, the resonance frequency of these antennas is 2.4 GHz, these antennas are suitable for ISM band and WLAN.
Implementation of Digital Beamforming Technique for Linear Antenna Arraysijsrd.com
A digital Beamforming technique used for increased channel capacity and also increased signal to noise and interference ratio. In smart antenna, different type of radiation pattern of an antenna can be changed either by selecting appropriate weights or by changing the array geometry. This paper presented based on auxiliary phase algorithm by using this algorithm in linear antenna array determine the array pattern approximating the auxiliary function in both amplitude and phase. Cost function involving auxiliary function and array pattern is minimized by modifying the pattern.
This document describes the design of a planar quasi-Yagi antenna capable of achieving high gain, wide bandwidth, and high front-to-back ratio. The antenna consists of a driven dipole element, reflector ground plane, and 5 director elements printed on a substrate. Optimization of the distances between the elements results in bandwidths over 600 MHz with gains above 6 dBi and front-to-back ratios greater than 34 dB. Measurements show good agreement with simulations, demonstrating this antenna design is suitable for applications requiring highly directive radiation patterns.
This document presents a new printed slot antenna design based on the first iteration of the Sierpinski gasket fractal geometry for dual band wireless communication applications. The antenna is fed by a microstrip transmission line and exhibits resonant behavior at 2.4 GHz and 5.2 GHz, making it suitable for dual band WLAN systems. Simulation results show the lower resonant band is determined by the slot size, while the feed length and position of a vertical stub affect the upper band matching and frequency. Parametric studies optimize the antenna for good impedance matching across both bands.
This document summarizes research on the design of octagon shaped slot loaded rectangular microstrip monopole antennas. The antennas are designed to operate across multiple frequency bands from 1-16 GHz and provide virtual size reduction. Experimental results show the proposed antenna operates over 8 bands with a maximum virtual size reduction of 62%. Modifying the antenna design by changing the radius of a circular slot inside the octagon allows operation over 5 bands while further increasing bandwidth and gain. The antennas demonstrate omnidirectional radiation patterns and have potential applications in microwave communication systems.
Pentagon and circular ring slot loaded rectangular microstrip monopoleIAEME Publication
The document describes the design and development of two pentagon and circular ring slot loaded rectangular microstrip monopole antennas (PCRSLRMA and PCCSLRMA) for quad-band and triple-band operation, respectively. The PCRSLRMA operates in four bands between 4-16 GHz while the PCCSLRMA operates in three bands. Both antennas exhibit omnidirectional radiation patterns. The PCRSLRMA achieves a maximum gain of 11.37 dB while the PCCSLRMA achieves 9.98 dB. The addition of the complementary circular ring slot in the PCCSLRMA enhances the bandwidth at each operating band compared to the PCRSLRMA. The proposed antennas have a simple
Design and development of low profile, dual band microstrip antenna with enha...IAEME Publication
This document describes the design and development of dual band microstrip antennas with enhanced bandwidth, gain, frequency ratio, and reduced cross polarization. It presents four antenna designs: a conventional rectangular microstrip antenna (CRMA), dual stub rectangular microstrip antenna (DSRMA), dual stub slot loaded rectangular microstrip antenna (DSSRMA), and triple stub slot loaded rectangular microstrip antenna (TSSRMA). Experimental results show that the TSSRMA design achieves a 21.13% upper operating bandwidth, 1.43 frequency ratio, 12.13 dB gain, and -20 dB cross polarization, demonstrating enhancements over the other designs without affecting broadside radiation characteristics.
Iisrt 3-design of rectangular patch antenna array using advanced design metho...IISRTJournals
This document describes the design of rectangular patch antenna arrays. It discusses designing a single patch element and determining its physical parameters. It then covers designing 1x2 and 2x2 array configurations using rectangular patches. The feed networks are designed using quarter-wave transformers to match impedances. Simulation results show the return loss and Smith charts with deep S11 values at the operating frequency of 2.4GHz, indicating good impedance matching.
Design of rectangular patch antenna array using advanced design methodologyIISRT
This document describes the design of rectangular patch antenna arrays. It discusses designing a single patch element, including selecting substrate properties and calculating patch dimensions. It then covers array design, including arranging elements with proper spacing and designing feed networks. Specifically, it presents the design of 1x2 and 2x2 rectangular patch antenna arrays. The key parameters discussed are return loss, VSWR, and impedance matching using techniques like quarter-wave transformers. Simulation results showing return loss and Smith charts are presented to validate the designed arrays operate as intended around 2.4GHz.
Design of rectangular patch antenna array using advanced design methodologyRamesh Patriotic
This document describes the design of rectangular patch antenna arrays. It discusses designing a single rectangular patch element, including selecting substrate properties and calculating patch dimensions. It then covers array design, including arranging elements with proper spacing and designing feed networks. Specifically, it presents the design of 1x2, 2x2, and 1x4 rectangular patch antenna arrays. Simulation results show the return loss and Smith charts for each array, indicating good impedance matching at the target frequency of 2.4GHz. Radiation patterns are also presented, demonstrating the increase in gain and directivity provided by antenna arrays.
Non-radiative wireless energy transfer with single layer dual-band printed sp...journalBEEI
Accomplishing equilibrium in terms of transfer efficiency for dual-band wireless energy transfer (WET) system remains as one of key concerns particularly in the implementation of a single transmitter device which supports simultaneous energy and data transfer functionality. Three stages of design method are discussed in addressing the aforementioned concern. A single layer dual-band printed spiral resonator for non-radiative wireless energy transfer operating at 6.78 MHz and 13.56 MHz is presented. By employing multi-coil approach, measured power transfer efficiency for a symmetrical link separated at axial distance of 30 mm are 72.34% and 74.02% at the respective frequency bands. When operating distance is varied between 30 mm to 38 mm, consistency of simulated peak transfer efficiency above 50% is achievable.
STUDY OF ARRAY BI-CONICAL ANTENNA FOR DME APPLICATIONSijwmn
This document summarizes the study of a linear array bi-conical antenna designed for Distance Measuring Equipment (DME) applications. The antenna consists of multiple bi-conical elements arranged in a linear configuration. Simulation results show that increasing the number of elements from 1 to 10 increases the maximum gain from 2 dB to 10.2 dB. This high gain linear array bi-conical antenna design is suitable for use in terrestrial DME ground stations due to its large size. The antenna operates within the DME frequency band of 960-1215 MHz.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Similar to Thinned Concentric Circular Array Antennas Synthesis using Improved Particle Swarm Optimization (20)
Power System State Estimation - A ReviewIDES Editor
This document provides a review of power system state estimation techniques. It discusses both static and dynamic state estimation algorithms. For static state estimation, it covers weighted least squares, decoupled, and robust estimation methods. Weighted least squares is commonly used but can have numerical instability issues. Decoupled state estimation approximates the gain matrix for faster computation. Robust estimation uses M-estimators and other techniques to handle outliers and bad data. Dynamic state estimation applies Kalman filtering, leapfrog algorithms, and other methods to continuously monitor system states over time.
Artificial Intelligence Technique based Reactive Power Planning Incorporating...IDES Editor
This document summarizes a research paper that proposes using artificial intelligence techniques and FACTS controllers for reactive power planning in real-time power transmission systems. The paper formulates the reactive power planning problem and incorporates flexible AC transmission system (FACTS) devices like static VAR compensators (SVC), thyristor controlled series capacitors (TCSC), and unified power flow controllers (UPFC). Evolutionary algorithms like evolutionary programming (EP) and differential evolution (DE) are applied to find the optimal locations and settings of the FACTS controllers to minimize losses and costs. Simulation results on IEEE 30-bus and 72-bus Indian test systems show that UPFC performs best in reducing losses compared to SVC and TCSC.
Design and Performance Analysis of Genetic based PID-PSS with SVC in a Multi-...IDES Editor
Damping of power system oscillations with the help
of proposed optimal Proportional Integral Derivative Power
System Stabilizer (PID-PSS) and Static Var Compensator
(SVC)-based controllers are thoroughly investigated in this
paper. This study presents robust tuning of PID-PSS and
SVC-based controllers using Genetic Algorithms (GA) in
multi machine power systems by considering detailed model
of the generators (model 1.1). The effectiveness of FACTSbased
controllers in general and SVC-based controller in
particular depends upon their proper location. Modal
controllability and observability are used to locate SVC–based
controller. The performance of the proposed controllers is
compared with conventional lead-lag power system stabilizer
(CPSS) and demonstrated on 10 machines, 39 bus New England
test system. Simulation studies show that the proposed genetic
based PID-PSS with SVC based controller provides better
performance.
Optimal Placement of DG for Loss Reduction and Voltage Sag Mitigation in Radi...IDES Editor
This paper presents the need to operate the power
system economically and with optimum levels of voltages has
further led to an increase in interest in Distributed
Generation. In order to reduce the power losses and to improve
the voltage in the distribution system, distributed generators
(DGs) are connected to load bus. To reduce the total power
losses in the system, the most important process is to identify
the proper location for fixing and sizing of DGs. It presents a
new methodology using a new population based meta heuristic
approach namely Artificial Bee Colony algorithm(ABC) for
the placement of Distributed Generators(DG) in the radial
distribution systems to reduce the real power losses and to
improve the voltage profile, voltage sag mitigation. The power
loss reduction is important factor for utility companies because
it is directly proportional to the company benefits in a
competitive electricity market, while reaching the better power
quality standards is too important as it has vital effect on
customer orientation. In this paper an ABC algorithm is
developed to gain these goals all together. In order to evaluate
sag mitigation capability of the proposed algorithm, voltage
in voltage sensitive buses is investigated. An existing 20KV
network has been chosen as test network and results are
compared with the proposed method in the radial distribution
system.
Line Losses in the 14-Bus Power System Network using UPFCIDES Editor
Controlling power flow in modern power systems
can be made more flexible by the use of recent developments
in power electronic and computing control technology. The
Unified Power Flow Controller (UPFC) is a Flexible AC
transmission system (FACTS) device that can control all the
three system variables namely line reactance, magnitude and
phase angle difference of voltage across the line. The UPFC
provides a promising means to control power flow in modern
power systems. Essentially the performance depends on proper
control setting achievable through a power flow analysis
program. This paper presents a reliable method to meet the
requirements by developing a Newton-Raphson based load
flow calculation through which control settings of UPFC can
be determined for the pre-specified power flow between the
lines. The proposed method keeps Newton-Raphson Load Flow
(NRLF) algorithm intact and needs (little modification in the
Jacobian matrix). A MATLAB program has been developed to
calculate the control settings of UPFC and the power flow
between the lines after the load flow is converged. Case studies
have been performed on IEEE 5-bus system and 14-bus system
to show that the proposed method is effective. These studies
indicate that the method maintains the basic NRLF properties
such as fast computational speed, high degree of accuracy and
good convergence rate.
Study of Structural Behaviour of Gravity Dam with Various Features of Gallery...IDES Editor
The size and shape of opening in dam causes the
stress concentration, it also causes the stress variation in the
rest of the dam cross section. The gravity method of the analysis
does not consider the size of opening and the elastic property
of dam material. Thus the objective of study is comprises of
the Finite Element Method which considers the size of
opening, elastic property of material, and stress distribution
because of geometric discontinuity in cross section of dam.
Stress concentration inside the dam increases with the opening
in dam which results in the failure of dam. Hence it is
necessary to analyses large opening inside the dam. By making
the percentage area of opening constant and varying size and
shape of opening the analysis is carried out. For this purpose
a section of Koyna Dam is considered. Dam is defined as a
plane strain element in FEM, based on geometry and loading
condition. Thus this available information specified our path
of approach to carry out 2D plane strain analysis. The results
obtained are then compared mutually to get most efficient
way of providing large opening in the gravity dam.
Assessing Uncertainty of Pushover Analysis to Geometric ModelingIDES Editor
Pushover Analysis a popular tool for seismic
performance evaluation of existing and new structures and is
nonlinear Static procedure where in monotonically increasing
loads are applied to the structure till the structure is unable
to resist the further load .During the analysis, whatever the
strength of concrete and steel is adopted for analysis of
structure may not be the same when real structure is
constructed and the pushover analysis results are very sensitive
to material model adopted, geometric model adopted, location
of plastic hinges and in general to procedure followed by the
analyzer. In this paper attempt has been made to assess
uncertainty in pushover analysis results by considering user
defined hinges and frame modeled as bare frame and frame
with slab modeled as rigid diaphragm and results compared
with experimental observations. Uncertain parameters
considered includes the strength of concrete, strength of steel
and cover to the reinforcement which are randomly generated
and incorporated into the analysis. The results are then
compared with experimental observations.
Secure Multi-Party Negotiation: An Analysis for Electronic Payments in Mobile...IDES Editor
This document summarizes and analyzes secure multi-party negotiation protocols for electronic payments in mobile computing. It presents a framework for secure multi-party decision protocols using lightweight implementations. The main focus is on synchronizing security features to avoid agreement manipulation and reduce user traffic. The paper describes negotiation between an auctioneer and bidders, showing multiparty security is better than existing systems. It analyzes the performance of encryption algorithms like ECC, XTR, and RSA for use in the multiparty negotiation protocols.
Selfish Node Isolation & Incentivation using Progressive ThresholdsIDES Editor
The problems associated with selfish nodes in
MANET are addressed by a collaborative watchdog approach
which reduces the detection time for selfish nodes thereby
improves the performance and accuracy of watchdogs[1]. In
the related works they make use of credit based systems, reputation
based mechanisms, pathrater and watchdog mechanism
to detect such selfish nodes. In this paper we follow an approach
of collaborative watchdog which reduces the detection
time for selfish nodes and also involves the removal of such
selfish nodes based on some progressively assessed thresholds.
The threshold gives the nodes a chance to stop misbehaving
before it is permanently deleted from the network.
The node passes through several isolation processes before it
is permanently removed. Another version of AODV protocol
is used here which allows the simulation of selfish nodes in
NS2 by adding or modifying log files in the protocol.
Various OSI Layer Attacks and Countermeasure to Enhance the Performance of WS...IDES Editor
Wireless sensor networks are networks having non
wired infrastructure and dynamic topology. In OSI model each
layer is prone to various attacks, which halts the performance
of a network .In this paper several attacks on four layers of
OSI model are discussed and security mechanism is described
to prevent attack in network layer i.e wormhole attack. In
Wormhole attack two or more malicious nodes makes a covert
channel which attracts the traffic towards itself by depicting a
low latency link and then start dropping and replaying packets
in the multi-path route. This paper proposes promiscuous mode
method to detect and isolate the malicious node during
wormhole attack by using Ad-hoc on demand distance vector
routing protocol (AODV) with omnidirectional antenna. The
methodology implemented notifies that the nodes which are
not participating in multi-path routing generates an alarm
message during delay and then detects and isolate the
malicious node from network. We also notice that not only
the same kind of attacks but also the same kind of
countermeasures can appear in multiple layer. For example,
misbehavior detection techniques can be applied to almost all
the layers we discussed.
Responsive Parameter based an AntiWorm Approach to Prevent Wormhole Attack in...IDES Editor
The recent advancements in the wireless technology
and their wide-spread deployment have made remarkable
enhancements in efficiency in the corporate and industrial
and Military sectors The increasing popularity and usage of
wireless technology is creating a need for more secure wireless
Ad hoc networks. This paper aims researched and developed
a new protocol that prevents wormhole attacks on a ad hoc
network. A few existing protocols detect wormhole attacks but
they require highly specialized equipment not found on most
wireless devices. This paper aims to develop a defense against
wormhole attacks as an Anti-worm protocol which is based on
responsive parameters, that does not require as a significant
amount of specialized equipment, trick clock synchronization,
no GPS dependencies.
Cloud Security and Data Integrity with Client Accountability FrameworkIDES Editor
This document summarizes a proposed cloud security and data integrity framework that provides client accountability. The framework aims to address issues like lack of user control over cloud data, need for data transparency and tracking, and ensuring data integrity. It proposes using JAR (Java Archive) files for data sharing due to benefits like portability. The framework incorporates client-side verification using MD5 hashing, digital signature-based authentication of JAR files, and use of HMAC to ensure data integrity. It also uses password-based encryption of log files to keep them tamper-proof. The framework is intended to provide both accountability and security for data sharing in cloud environments.
Genetic Algorithm based Layered Detection and Defense of HTTP BotnetIDES Editor
A System state in HTTP botnet uses HTTP protocol
for the creation of chain of Botnets thereby compromising
other systems. By using HTTP protocol and port number 80,
attacks can not only be hidden but also pass through the
firewall without being detected. The DPR based detection
leads to better analysis of botnet attacks [3]. However, it
provides only probabilistic detection of the attacker and also
time consuming and error prone. This paper proposes a Genetic
algorithm based layered approach for detecting as well as
preventing botnet attacks. The paper reviews p2p firewall
implementation which forms the basis of filtering.
Performance evaluation is done based on precision, F-value
and probability. Layered approach reduces the computation
and overall time requirement [7]. Genetic algorithm promises
a low false positive rate.
Enhancing Data Storage Security in Cloud Computing Through SteganographyIDES Editor
This document summarizes a research paper that proposes a method for enhancing data security in cloud computing through steganography. The method hides user data in digital images stored on cloud servers. When data needs to be accessed, it is extracted from the images. The document outlines the cloud architecture and security issues addressed. It then describes the proposed system architecture, security model, and data storage and retrieval process. Data is partitioned and hidden in multiple images to improve security. The goal is to prevent unauthorized access to user data stored on cloud servers.
The main tasks of a Wireless Sensor Network
(WSN) are data collection from its nodes and communication
of this data to the base station (BS). The protocols used for
communication among the WSN nodes and between the WSN
and the BS, must consider the resource constraints of nodes,
battery energy, computational capabilities and memory. The
WSN applications involve unattended operation of the network
over an extended period of time. In order to extend the lifetime
of a WSN, efficient routing protocols need to be adopted. The
proposed low power routing protocol based on tree-based
network structure reliably forwards the measured data towards
the BS using TDMA. An energy consumption analysis of the
WSN making use of this protocol is also carried out. It is
found that the network is energy efficient with an average
duty cycle of 0:7% for the WSN nodes. The OmNET++
simulation platform along with MiXiM framework is made
use of.
Permutation of Pixels within the Shares of Visual Cryptography using KBRP for...IDES Editor
The security of authentication of internet based
co-banking services should not be susceptible to high risks.
The passwords are highly vulnerable to virus attacks due to
the lack of high end embedding of security methods. In order
for the passwords to be more secure, people are generally
compelled to select jumbled up character based passwords
which are not only less memorable but are also equally prone
to insecurity. Multiple use of distributed shares has been
studied to solve the problem of authentication by algorithms
based on thresholding of pixels in image processing and visual
cryptography concepts where the subset of shares is considered
for the recovery of the original image for authentication using
correlation function[1][2].The main disadvantage in the above
study is the plain storage of shares and also one of the shares
is being supplied to the customer, which will lead to the
possibility of misuse by a third party. This paper proposes a
technique for scrambling of pixels by key based random
permutation (KBRP) within the shares before the
authentication has been attempted. Total number of shares to
be created is dependent on the multiplicity of ownership of
the account. By this method the problem of uncertainty among
the customers with regard to security, storage, retrieval of
holding of half of the shares is minimized.
This paper presents a trifocal Rotman Lens Design
approach. The effects of focal ratio and element spacing on
the performance of Rotman Lens are described. A three beam
prototype feeding 4 element antenna array working in L-band
has been simulated using RLD v1.7 software. Simulated
results show that the simulated lens has a return loss of –
12.4dB at 1.8GHz. Beam to array port phase error variation
with change in the focal ratio and element spacing has also
been investigated.
Band Clustering for the Lossless Compression of AVIRIS Hyperspectral ImagesIDES Editor
Hyperspectral images can be efficiently compressed
through a linear predictive model, as for example the one
used in the SLSQ algorithm. In this paper we exploit this
predictive model on the AVIRIS images by individuating,
through an off-line approach, a common subset of bands, which
are not spectrally related with any other bands. These bands
are not useful as prediction reference for the SLSQ 3-D
predictive model and we need to encode them via other
prediction strategies which consider only spatial correlation.
We have obtained this subset by clustering the AVIRIS bands
via the clustering by compression approach. The main result
of this paper is the list of the bands, not related with the
others, for AVIRIS images. The clustering trees obtained for
AVIRIS and the relationship among bands they depict is also
an interesting starting point for future research.
Microelectronic Circuit Analogous to Hydrogen Bonding Network in Active Site ...IDES Editor
A microelectronic circuit of block-elements
functionally analogous to two hydrogen bonding networks is
investigated. The hydrogen bonding networks are extracted
from â-lactamase protein and are formed in its active site.
Each hydrogen bond of the network is described in equivalent
electrical circuit by three or four-terminal block-element.
Each block-element is coded in Matlab. Static and dynamic
analyses are performed. The resultant microelectronic circuit
analogous to the hydrogen bonding network operates as
current mirror, sine pulse source, triangular pulse source as
well as signal modulator.
Texture Unit based Monocular Real-world Scene Classification using SOM and KN...IDES Editor
In this paper a method is proposed to discriminate
real world scenes in to natural and manmade scenes of similar
depth. Global-roughness of a scene image varies as a function
of image-depth. Increase in image depth leads to increase in
roughness in manmade scenes; on the contrary natural scenes
exhibit smooth behavior at higher image depth. This particular
arrangement of pixels in scene structure can be well explained
by local texture information in a pixel and its neighborhood.
Our proposed method analyses local texture information of a
scene image using texture unit matrix. For final classification
we have used both supervised and unsupervised learning using
K-Nearest Neighbor classifier (KNN) and Self Organizing
Map (SOM) respectively. This technique is useful for online
classification due to very less computational complexity.
For the full video of this presentation, please visit: https://www.edge-ai-vision.com/2024/06/temporal-event-neural-networks-a-more-efficient-alternative-to-the-transformer-a-presentation-from-brainchip/
Chris Jones, Director of Product Management at BrainChip , presents the “Temporal Event Neural Networks: A More Efficient Alternative to the Transformer” tutorial at the May 2024 Embedded Vision Summit.
The expansion of AI services necessitates enhanced computational capabilities on edge devices. Temporal Event Neural Networks (TENNs), developed by BrainChip, represent a novel and highly efficient state-space network. TENNs demonstrate exceptional proficiency in handling multi-dimensional streaming data, facilitating advancements in object detection, action recognition, speech enhancement and language model/sequence generation. Through the utilization of polynomial-based continuous convolutions, TENNs streamline models, expedite training processes and significantly diminish memory requirements, achieving notable reductions of up to 50x in parameters and 5,000x in energy consumption compared to prevailing methodologies like transformers.
Integration with BrainChip’s Akida neuromorphic hardware IP further enhances TENNs’ capabilities, enabling the realization of highly capable, portable and passively cooled edge devices. This presentation delves into the technical innovations underlying TENNs, presents real-world benchmarks, and elucidates how this cutting-edge approach is positioned to revolutionize edge AI across diverse applications.
"Choosing proper type of scaling", Olena SyrotaFwdays
Imagine an IoT processing system that is already quite mature and production-ready and for which client coverage is growing and scaling and performance aspects are life and death questions. The system has Redis, MongoDB, and stream processing based on ksqldb. In this talk, firstly, we will analyze scaling approaches and then select the proper ones for our system.
[OReilly Superstream] Occupy the Space: A grassroots guide to engineering (an...Jason Yip
The typical problem in product engineering is not bad strategy, so much as “no strategy”. This leads to confusion, lack of motivation, and incoherent action. The next time you look for a strategy and find an empty space, instead of waiting for it to be filled, I will show you how to fill it in yourself. If you’re wrong, it forces a correction. If you’re right, it helps create focus. I’ll share how I’ve approached this in the past, both what works and lessons for what didn’t work so well.
Have you ever been confused by the myriad of choices offered by AWS for hosting a website or an API?
Lambda, Elastic Beanstalk, Lightsail, Amplify, S3 (and more!) can each host websites + APIs. But which one should we choose?
Which one is cheapest? Which one is fastest? Which one will scale to meet our needs?
Join me in this session as we dive into each AWS hosting service to determine which one is best for your scenario and explain why!
Dandelion Hashtable: beyond billion requests per second on a commodity serverAntonios Katsarakis
This slide deck presents DLHT, a concurrent in-memory hashtable. Despite efforts to optimize hashtables, that go as far as sacrificing core functionality, state-of-the-art designs still incur multiple memory accesses per request and block request processing in three cases. First, most hashtables block while waiting for data to be retrieved from memory. Second, open-addressing designs, which represent the current state-of-the-art, either cannot free index slots on deletes or must block all requests to do so. Third, index resizes block every request until all objects are copied to the new index. Defying folklore wisdom, DLHT forgoes open-addressing and adopts a fully-featured and memory-aware closed-addressing design based on bounded cache-line-chaining. This design offers lock-free index operations and deletes that free slots instantly, (2) completes most requests with a single memory access, (3) utilizes software prefetching to hide memory latencies, and (4) employs a novel non-blocking and parallel resizing. In a commodity server and a memory-resident workload, DLHT surpasses 1.6B requests per second and provides 3.5x (12x) the throughput of the state-of-the-art closed-addressing (open-addressing) resizable hashtable on Gets (Deletes).
zkStudyClub - LatticeFold: A Lattice-based Folding Scheme and its Application...Alex Pruden
Folding is a recent technique for building efficient recursive SNARKs. Several elegant folding protocols have been proposed, such as Nova, Supernova, Hypernova, Protostar, and others. However, all of them rely on an additively homomorphic commitment scheme based on discrete log, and are therefore not post-quantum secure. In this work we present LatticeFold, the first lattice-based folding protocol based on the Module SIS problem. This folding protocol naturally leads to an efficient recursive lattice-based SNARK and an efficient PCD scheme. LatticeFold supports folding low-degree relations, such as R1CS, as well as high-degree relations, such as CCS. The key challenge is to construct a secure folding protocol that works with the Ajtai commitment scheme. The difficulty, is ensuring that extracted witnesses are low norm through many rounds of folding. We present a novel technique using the sumcheck protocol to ensure that extracted witnesses are always low norm no matter how many rounds of folding are used. Our evaluation of the final proof system suggests that it is as performant as Hypernova, while providing post-quantum security.
Paper Link: https://eprint.iacr.org/2024/257
HCL Notes und Domino Lizenzkostenreduzierung in der Welt von DLAUpanagenda
Webinar Recording: https://www.panagenda.com/webinars/hcl-notes-und-domino-lizenzkostenreduzierung-in-der-welt-von-dlau/
DLAU und die Lizenzen nach dem CCB- und CCX-Modell sind für viele in der HCL-Community seit letztem Jahr ein heißes Thema. Als Notes- oder Domino-Kunde haben Sie vielleicht mit unerwartet hohen Benutzerzahlen und Lizenzgebühren zu kämpfen. Sie fragen sich vielleicht, wie diese neue Art der Lizenzierung funktioniert und welchen Nutzen sie Ihnen bringt. Vor allem wollen Sie sicherlich Ihr Budget einhalten und Kosten sparen, wo immer möglich. Das verstehen wir und wir möchten Ihnen dabei helfen!
Wir erklären Ihnen, wie Sie häufige Konfigurationsprobleme lösen können, die dazu führen können, dass mehr Benutzer gezählt werden als nötig, und wie Sie überflüssige oder ungenutzte Konten identifizieren und entfernen können, um Geld zu sparen. Es gibt auch einige Ansätze, die zu unnötigen Ausgaben führen können, z. B. wenn ein Personendokument anstelle eines Mail-Ins für geteilte Mailboxen verwendet wird. Wir zeigen Ihnen solche Fälle und deren Lösungen. Und natürlich erklären wir Ihnen das neue Lizenzmodell.
Nehmen Sie an diesem Webinar teil, bei dem HCL-Ambassador Marc Thomas und Gastredner Franz Walder Ihnen diese neue Welt näherbringen. Es vermittelt Ihnen die Tools und das Know-how, um den Überblick zu bewahren. Sie werden in der Lage sein, Ihre Kosten durch eine optimierte Domino-Konfiguration zu reduzieren und auch in Zukunft gering zu halten.
Diese Themen werden behandelt
- Reduzierung der Lizenzkosten durch Auffinden und Beheben von Fehlkonfigurationen und überflüssigen Konten
- Wie funktionieren CCB- und CCX-Lizenzen wirklich?
- Verstehen des DLAU-Tools und wie man es am besten nutzt
- Tipps für häufige Problembereiche, wie z. B. Team-Postfächer, Funktions-/Testbenutzer usw.
- Praxisbeispiele und Best Practices zum sofortigen Umsetzen
Fueling AI with Great Data with Airbyte WebinarZilliz
This talk will focus on how to collect data from a variety of sources, leveraging this data for RAG and other GenAI use cases, and finally charting your course to productionalization.
Digital Banking in the Cloud: How Citizens Bank Unlocked Their MainframePrecisely
Inconsistent user experience and siloed data, high costs, and changing customer expectations – Citizens Bank was experiencing these challenges while it was attempting to deliver a superior digital banking experience for its clients. Its core banking applications run on the mainframe and Citizens was using legacy utilities to get the critical mainframe data to feed customer-facing channels, like call centers, web, and mobile. Ultimately, this led to higher operating costs (MIPS), delayed response times, and longer time to market.
Ever-changing customer expectations demand more modern digital experiences, and the bank needed to find a solution that could provide real-time data to its customer channels with low latency and operating costs. Join this session to learn how Citizens is leveraging Precisely to replicate mainframe data to its customer channels and deliver on their “modern digital bank” experiences.
The Microsoft 365 Migration Tutorial For Beginner.pptxoperationspcvita
This presentation will help you understand the power of Microsoft 365. However, we have mentioned every productivity app included in Office 365. Additionally, we have suggested the migration situation related to Office 365 and how we can help you.
You can also read: https://www.systoolsgroup.com/updates/office-365-tenant-to-tenant-migration-step-by-step-complete-guide/
For the full video of this presentation, please visit: https://www.edge-ai-vision.com/2024/06/how-axelera-ai-uses-digital-compute-in-memory-to-deliver-fast-and-energy-efficient-computer-vision-a-presentation-from-axelera-ai/
Bram Verhoef, Head of Machine Learning at Axelera AI, presents the “How Axelera AI Uses Digital Compute-in-memory to Deliver Fast and Energy-efficient Computer Vision” tutorial at the May 2024 Embedded Vision Summit.
As artificial intelligence inference transitions from cloud environments to edge locations, computer vision applications achieve heightened responsiveness, reliability and privacy. This migration, however, introduces the challenge of operating within the stringent confines of resource constraints typical at the edge, including small form factors, low energy budgets and diminished memory and computational capacities. Axelera AI addresses these challenges through an innovative approach of performing digital computations within memory itself. This technique facilitates the realization of high-performance, energy-efficient and cost-effective computer vision capabilities at the thin and thick edge, extending the frontier of what is achievable with current technologies.
In this presentation, Verhoef unveils his company’s pioneering chip technology and demonstrates its capacity to deliver exceptional frames-per-second performance across a range of standard computer vision networks typical of applications in security, surveillance and the industrial sector. This shows that advanced computer vision can be accessible and efficient, even at the very edge of our technological ecosystem.
Ivanti’s Patch Tuesday breakdown goes beyond patching your applications and brings you the intelligence and guidance needed to prioritize where to focus your attention first. Catch early analysis on our Ivanti blog, then join industry expert Chris Goettl for the Patch Tuesday Webinar Event. There we’ll do a deep dive into each of the bulletins and give guidance on the risks associated with the newly-identified vulnerabilities.
Programming Foundation Models with DSPy - Meetup SlidesZilliz
Prompting language models is hard, while programming language models is easy. In this talk, I will discuss the state-of-the-art framework DSPy for programming foundation models with its powerful optimizers and runtime constraint system.