This document discusses using Particle Swarm Optimization (PSO) to design a tapered microstrip transmission line to match an arbitrary load to a 50Ω line. PSO was used to optimize the impedances of a three section tapered line to minimize reflections. Simulations found impedances that gave good matching at 5GHz. PSO converged to solutions in under 1000 iterations. This demonstrates PSO's effectiveness in solving multi-objective microwave engineering optimization problems.
Effect of Material Thickness on Attenuation (dB) of PTFE Using Finite Element...Abubakar Yakubu
This research article examines how the thickness of polytetrafluoroethylene (PTFE) samples affects the attenuation of electromagnetic waves at X-band frequency using finite element method (FEM) simulations. The results show that as the thickness of the PTFE samples increases, the attenuation also increases. Specifically, the 15 mm thick PTFE sample has an attenuation of -3.32 dB, the 30 mm sample has an attenuation of 0.64 dB, and the 50 mm sample has an attenuation of 1.97 dB. The study finds that increasing sample thickness leads to a decrease in electromagnetic wave transmission and an increase in attenuation.
A detailed analysis of three major dynamics and Non Linear analysis was done, which included:
1. Normal Modes and Frequency Response Analysis (FRA).
2. Large Deformation, Geometric Non-Linearity.
3. Elastoplastic Material Analysis, Material Non-Linearity.
1. A finite element analysis was conducted on an original aluminum bicycle crankarm design and three redesigns to reduce weight by at least 50% while maintaining structural integrity.
2. The optimal mesh was determined to be a Sweep (Quad/Tri) mesh with an element size of 2.5mm based on convergence of maximum deformation values.
3. Analysis of the original design found maximum deformation and stress occurred at 90 degrees of applied force. Redesign 1, a basic I-beam shape, reduced mass by 59.53% while maintaining lowest structural stresses and errors.
Reliability Evaluation of Low-voltage Switchgear Based on Maximum Entropy Pri...TELKOMNIKA JOURNAL
In this paper, based on the definition of two-parameter joint entropy and the maximum entropy principle, a method was proposed to determine the prior distribution by using the maximum entropy method in the reliability evaluation of low-voltage switchgear. The maximum entropy method takes kinds of priori information as different constraints. The optimal prior distribution was selected by maximizing entropy under these constraints, which not only contains the known prior information but also tries to avoid the introduction of other assumption information. Based on non-parametric bootstrap method, the hyper-parameters of prior distribution is obtained by two-order moment of prior information. Finally, with the bootstrap method, the prior distribution robustness and the posterior robustness were analyzed, and the posterior mean time between failures for the low-voltage switchgear was estimated.
An image can be seen as a matrix I, where I(x, y) is the brightness of the pixel located at coordinates (x, y). In the Convolutional neural network, the kernel is nothing but a filter
that is used to extract the features from the images.
Molecular Activity Prediction Using Graph Convolutional Deep Neural Network C...Masahito Ohue
Molecular Activity Prediction Using Graph Convolutional Deep Neural Network Considering Distance on a Molecular Graph
Int’l Workshop on Mathematical Modeling and Problem Solving (MPS)
2019 Int’l Conference on Parallel and Distributed Processing Techniques & Applications (PDPTA’19)
Session 2. July 29, 2019 @Luxor, Las Vegas
https://americancse.org/events/csce2019/program/pdp_csc_ipc_msv_gcc_29
This document discusses vibration energy harvesting in uncertain environments. It begins with an introduction that describes piezoelectric vibration energy harvesting and the importance of considering uncertainty in both the input excitation and system parameters. It then presents single degree of freedom electromechanical models for linear and nonlinear energy harvesting systems. Optimal energy harvesting is analyzed for a linear system with a circuit without an inductor, where the mean harvested power is derived under Gaussian excitation.
DriP PSO- A fast and inexpensive PSO for drifting problem spacesZubin Bhuyan
Particle Swarm Optimization is a class of stochastic, population based optimization techniques which are mostly suitable for static problems. However, real world optimization problems are time variant, i.e., the problem space changes over time. Several researches have been done to address this dynamic optimization problem using Particle Swarms. In this paper we probe the issues of tracking and optimizing Particle Swarms in a dynamic system where the problem-space drifts in a particular direction. Our assumption is that the approximate amount of drift is known, but the direction of the drift is unknown. We propose a Drift Predictive PSO (DriP-PSO) model which does not incur high computation cost, and is very fast and accurate. The main idea behind this technique is to use a few stagnant particles to determine the approximate direction in which the problem-space is drifting so that the particle velocities may be adjusted accordingly in the subsequent iteration of the algorithm.
Effect of Material Thickness on Attenuation (dB) of PTFE Using Finite Element...Abubakar Yakubu
This research article examines how the thickness of polytetrafluoroethylene (PTFE) samples affects the attenuation of electromagnetic waves at X-band frequency using finite element method (FEM) simulations. The results show that as the thickness of the PTFE samples increases, the attenuation also increases. Specifically, the 15 mm thick PTFE sample has an attenuation of -3.32 dB, the 30 mm sample has an attenuation of 0.64 dB, and the 50 mm sample has an attenuation of 1.97 dB. The study finds that increasing sample thickness leads to a decrease in electromagnetic wave transmission and an increase in attenuation.
A detailed analysis of three major dynamics and Non Linear analysis was done, which included:
1. Normal Modes and Frequency Response Analysis (FRA).
2. Large Deformation, Geometric Non-Linearity.
3. Elastoplastic Material Analysis, Material Non-Linearity.
1. A finite element analysis was conducted on an original aluminum bicycle crankarm design and three redesigns to reduce weight by at least 50% while maintaining structural integrity.
2. The optimal mesh was determined to be a Sweep (Quad/Tri) mesh with an element size of 2.5mm based on convergence of maximum deformation values.
3. Analysis of the original design found maximum deformation and stress occurred at 90 degrees of applied force. Redesign 1, a basic I-beam shape, reduced mass by 59.53% while maintaining lowest structural stresses and errors.
Reliability Evaluation of Low-voltage Switchgear Based on Maximum Entropy Pri...TELKOMNIKA JOURNAL
In this paper, based on the definition of two-parameter joint entropy and the maximum entropy principle, a method was proposed to determine the prior distribution by using the maximum entropy method in the reliability evaluation of low-voltage switchgear. The maximum entropy method takes kinds of priori information as different constraints. The optimal prior distribution was selected by maximizing entropy under these constraints, which not only contains the known prior information but also tries to avoid the introduction of other assumption information. Based on non-parametric bootstrap method, the hyper-parameters of prior distribution is obtained by two-order moment of prior information. Finally, with the bootstrap method, the prior distribution robustness and the posterior robustness were analyzed, and the posterior mean time between failures for the low-voltage switchgear was estimated.
An image can be seen as a matrix I, where I(x, y) is the brightness of the pixel located at coordinates (x, y). In the Convolutional neural network, the kernel is nothing but a filter
that is used to extract the features from the images.
Molecular Activity Prediction Using Graph Convolutional Deep Neural Network C...Masahito Ohue
Molecular Activity Prediction Using Graph Convolutional Deep Neural Network Considering Distance on a Molecular Graph
Int’l Workshop on Mathematical Modeling and Problem Solving (MPS)
2019 Int’l Conference on Parallel and Distributed Processing Techniques & Applications (PDPTA’19)
Session 2. July 29, 2019 @Luxor, Las Vegas
https://americancse.org/events/csce2019/program/pdp_csc_ipc_msv_gcc_29
This document discusses vibration energy harvesting in uncertain environments. It begins with an introduction that describes piezoelectric vibration energy harvesting and the importance of considering uncertainty in both the input excitation and system parameters. It then presents single degree of freedom electromechanical models for linear and nonlinear energy harvesting systems. Optimal energy harvesting is analyzed for a linear system with a circuit without an inductor, where the mean harvested power is derived under Gaussian excitation.
DriP PSO- A fast and inexpensive PSO for drifting problem spacesZubin Bhuyan
Particle Swarm Optimization is a class of stochastic, population based optimization techniques which are mostly suitable for static problems. However, real world optimization problems are time variant, i.e., the problem space changes over time. Several researches have been done to address this dynamic optimization problem using Particle Swarms. In this paper we probe the issues of tracking and optimizing Particle Swarms in a dynamic system where the problem-space drifts in a particular direction. Our assumption is that the approximate amount of drift is known, but the direction of the drift is unknown. We propose a Drift Predictive PSO (DriP-PSO) model which does not incur high computation cost, and is very fast and accurate. The main idea behind this technique is to use a few stagnant particles to determine the approximate direction in which the problem-space is drifting so that the particle velocities may be adjusted accordingly in the subsequent iteration of the algorithm.
This document discusses the principle of minimum potential energy (MPE) and its application in finite element analysis of structures. MPE states that for conservative structural systems, the equilibrium state corresponds to the deformation that minimizes the total potential energy of the system. The document provides examples of applying MPE to simple spring-mass systems to derive equilibrium equations, and discusses how continuous systems can be approximated by discretizing them into lumped finite elements, allowing complex structures to be analyzed systematically using MPE.
The International Journal of Engineering and Science (The IJES)theijes
This document summarizes a research paper that proposes a novel approach to improving the k-means clustering algorithm. The standard k-means algorithm is computationally expensive and produces results that depend heavily on the initial centroid selection. The proposed approach determines initial centroids systematically and uses a heuristic to efficiently assign data points to clusters. It improves both the accuracy and efficiency of k-means clustering by ensuring the entire process takes O(n2) time without sacrificing cluster quality.
Improving EV Lateral Dynamics Control Using Infinity Norm Approach with Close...Valerio Salvucci
This document presents two approaches for resolving actuator redundancy in electric vehicles (EVs) - the 2 norm approach using a pseudo-inverse matrix and the infinity norm approach proposed by the authors. The infinity norm approach provides a closed-form solution and fully utilizes the input range, avoiding actuator saturation. Simulations in CarSim show the infinity norm approach performs better than the 2 norm approach, maintaining stability at higher speeds and steering commands where the 2 norm approach results in actuator saturation and instability.
Multi-Objective Genetic Topological Optimization for Design of composite wall...Sardasht S. Weli
The aim of this presentation is to show the utilization of Topology Optimization to optimize a wall barrier thickness and its resistance under the extreme environment which is blast loading.
This document discusses the Ewald summation method, which is a technique for efficiently calculating long-range electrostatic interactions in systems with periodic boundary conditions. It separates interactions into short-range and long-range parts for faster calculation. The method decomposes the lattice sum into real space and reciprocal space contributions. It also discusses applications of the Ewald summation method, including for uniformly charged surfaces, using fast Fourier transforms to improve computation time, and calculating interactions between molecules.
Research on Transformer Core Vibration under DC Bias Based on Multi-field Cou...inventionjournals
The Mathematical models for DC bias vibration analysis of the transformer core are developed in this paper. The model is combined into multi-physical field coupling modeling for vibration analysis of the transformer. By applying the primary voltage as excitation and under different DC bias, vibrations of the transformer core is simulated and analyzed.
My research at Boston University (May 2013)
1. Thesis: Viscoelastic testing and modeling of PDMS micropillars for cellular force measurement
2. Side Projects
1) Conducting polymer actuators
2) PDMS and conducting polymer nanowire composites
3) Silicon oxycarbide thin films
4) Tribological study of DLC coatings
IRJET- Free Vibration Analysis of BeamsIRJET Journal
The document analyzes the free vibration of beams with different cross-sections, materials, and support conditions. It presents analytical equations based on Euler-Bernoulli beam theory to calculate the natural frequencies of beams. Tables show the fundamental natural frequencies of steel and aluminum beams with circular and rectangular cross-sections in cantilever and simply supported conditions, as calculated analytically and using ANSYS software. The results from both methods show good correlation. Plots of natural frequency versus geometric parameters like diameter and depth are also presented. The study aims to determine the most efficient cross-section and material for structural design by comparing the vibration characteristics.
Efficient mode-matching analysis of 2-D scattering by periodic array of circu...Yong Heui Cho
This document proposes a new mode-matching method for analyzing periodic arrays of circular cylinders with different materials. It uses a common-area concept and infinitesimal perfect magnetic conductor wires to match boundary conditions between rectangular and cylindrical coordinate systems. This allows derivation of scattering equations for the arrays. The solutions are compared to other results to validate the method. It can be used to study resonance characteristics of nanostructures and scattering behavior at different frequencies.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Tomography is important for network design and routing optimization. Prior approaches require either
precise time synchronization or complex cooperation. Furthermore, active tomography consumes explicit
probing resulting in limited scalability. To address the first issue we propose a novel Delay Correlation
Estimation methodology named DCE with no need of synchronization and special cooperation. For the
second issue we develop a passive realization mechanism merely using regular data flow without explicit
bandwidth consumption. Extensive simulations in OMNeT++ are made to evaluate its accuracy where we
show that DCE measurement is highly identical with the true value. Also from test result we find that
mechanism of passive realization is able to achieve both regular data transmission and purpose of
tomography with excellent robustness versus different background traffic and package size.
The International Journal of Engineering and Sciencetheijes
1. The document analyzes the behavior of transmission probability in a single rectangular potential barrier where the barrier height and width are scaled by a common factor such that their product remains constant.
2. Expressions for transmission probability are derived for three cases: particle energy greater than, equal to, and less than the barrier energy. Approximations are used to express transmission probability in terms of the constant barrier height-width product.
3. The results show that transmission probability remains constant for particle energy greater than and less than the barrier energy. However, transmission probability decreases with decreasing particle energy when it is equal to the barrier energy.
The document discusses interference of electromagnetic waves. It explains that the intensity of two waves added together can be calculated using an equation that takes into account the individual intensities, wavelength, and phase difference between the waves. It then provides an example problem where the individual intensities, wavelength, and distance between two waves are given, and calculates the total intensity when the waves are combined using the interference equation.
The document summarizes research determining the optical constants and thickness of tin oxide (SnO2) thin films. Ellipsometry was used to measure the delta and psi values of the thin film coated on a glass substrate. Software analysis of the ellipsometry data found the refractive index of the SnO2 film to be 1.517 and the thickness to be 250 nm. Additional modeling of the complex dielectric function was also discussed to better understand the optical properties of conductive thin films like SnO2.
Vibration Analysis and Modelling of a Cantilever Beam Muhammad Usman
This report in cooperates the techniques, adopted for the evaluation of vibration analysis of a cantilever beam using both techniques i.e. theoretical as well as the practical ones. Computer based analysis of a beam were also performed using Solid Works and Mat Lab software. These techniques helped a lot in finding the natural frequencies and in making the vibrational characteristic behavior of a cantilever beam thus steel used as a material.
Investigation of General Equation That Best Describe the Relationship between...IOSR Journals
This document investigates the general equation that best describes the relationship between survival fraction and critical mass of uranium-235. Monte Carlo simulations were used to study neutron interactions in rectangular uranium-235 geometries. Two models, a cubic equation and logarithmic equation, were tested against observed data from simulations with varying ratios of length to thickness. Statistical analysis showed that the logarithmic equation provided a better fit, with regression values closer to 1. Therefore, the logarithmic equation best describes the relationship between survival fraction and critical mass of uranium-235.
This chapter discusses theoretical models for analyzing piezoelectric fiber composites (PFCs) subjected to push-out and pull-out tests. It presents the basic formulations and assumptions used in the micromechanical model of a single piezoelectric fiber embedded in a polymer matrix. Constitutive equations are provided for the fiber and matrix. Equations are developed relating the stresses and electric fields in the fiber and matrix. Models are then described for analyzing the stress distributions and electric fields in the fiber under both mechanical and electric loads for cases of a perfectly bonded interface and a frictional sliding interface after debonding.
This document summarizes a study that uses the Alternating Direction Implicit Finite-Difference Time-Domain (ADI-FDTD) method to simulate high speed interconnect structures. Specifically, it simulates Coplanar Waveguide (CPW) and Stacked Grounded Coplanar Waveguide (SGCPW) structures to calculate electrical parameters and analyze signal integrity. The ADI-FDTD method is presented and applied to Yee's staggered grid to solve Maxwell's equations without the Courant–Friedrich–Levy stability condition, allowing a larger time step. Numerical simulations compare the CPU run time of ADI-FDTD and standard FDTD for a CPW structure, showing that ADI-FDTD
11.signal integrity analysis of modified coplanar waveguide structure using a...Alexander Decker
This document summarizes a study that uses the Alternating Direction Implicit Finite-Difference Time-Domain (ADI-FDTD) method to simulate high speed interconnect structures. Specifically, it simulates Coplanar Waveguide (CPW) and Stacked Grounded Coplanar Waveguide (SGCPW) structures to calculate electrical parameters and analyze signal integrity. The ADI-FDTD method is presented as an improvement over traditional FDTD as it eliminates constraints on time step size. Simulation results show that ADI-FDTD takes less CPU time than FDTD for analyzing the same structures.
This paper analyses the optimal power system planning with DGs used as real and reactive power compensator. Recently planning of DG placement reactive power compensation are the major problems in distribution system. As the requirement in the power is more the DG placement becomes important. When planned to make the DG placement, cost analysis becomes as a major concern. And if the DGs operate as reactive power compensator it is most helpful in power quality maintenance. So, this paper deals with the optimal power system planning with renewable DGs which can be used as a reactive power compensators. The problem is formulated and solved using popular meta-heuristic techniques called cuckoo search algorithm (CSA) and particle swarm optimization (PSO). the comparative results are presented.
This summary provides an overview of the key points from the document:
1) The document presents the use of General Regression Neural Networks (GRNN) to predict propagation path loss in an urban environment based on measurements taken in Kavala, Greece.
2) Two neural network models are studied - one for path loss prediction and another using error control. Their performance is compared to measured path loss values based on error metrics.
3) For line-of-sight predictions, the GRNN model achieves better performance than empirical models due to using multiple input parameters and generalization. For non-line-of-sight, a third GRNN model including street orientation has the lowest error rates.
This document summarizes research on using particle swarm optimization to reconstruct microwave images of two-dimensional dielectric scatterers. It formulates the inverse scattering problem as an optimization problem to find the dielectric parameter distribution that minimizes the difference between measured and simulated scattered field data. Numerical results show that a particle swarm optimization approach can accurately reconstruct the shape and dielectric properties of a test cylindrical scatterer, with lower background reconstruction error than a genetic algorithm approach. The research demonstrates that particle swarm optimization is a suitable technique for high-dimensional microwave imaging problems.
This document discusses the principle of minimum potential energy (MPE) and its application in finite element analysis of structures. MPE states that for conservative structural systems, the equilibrium state corresponds to the deformation that minimizes the total potential energy of the system. The document provides examples of applying MPE to simple spring-mass systems to derive equilibrium equations, and discusses how continuous systems can be approximated by discretizing them into lumped finite elements, allowing complex structures to be analyzed systematically using MPE.
The International Journal of Engineering and Science (The IJES)theijes
This document summarizes a research paper that proposes a novel approach to improving the k-means clustering algorithm. The standard k-means algorithm is computationally expensive and produces results that depend heavily on the initial centroid selection. The proposed approach determines initial centroids systematically and uses a heuristic to efficiently assign data points to clusters. It improves both the accuracy and efficiency of k-means clustering by ensuring the entire process takes O(n2) time without sacrificing cluster quality.
Improving EV Lateral Dynamics Control Using Infinity Norm Approach with Close...Valerio Salvucci
This document presents two approaches for resolving actuator redundancy in electric vehicles (EVs) - the 2 norm approach using a pseudo-inverse matrix and the infinity norm approach proposed by the authors. The infinity norm approach provides a closed-form solution and fully utilizes the input range, avoiding actuator saturation. Simulations in CarSim show the infinity norm approach performs better than the 2 norm approach, maintaining stability at higher speeds and steering commands where the 2 norm approach results in actuator saturation and instability.
Multi-Objective Genetic Topological Optimization for Design of composite wall...Sardasht S. Weli
The aim of this presentation is to show the utilization of Topology Optimization to optimize a wall barrier thickness and its resistance under the extreme environment which is blast loading.
This document discusses the Ewald summation method, which is a technique for efficiently calculating long-range electrostatic interactions in systems with periodic boundary conditions. It separates interactions into short-range and long-range parts for faster calculation. The method decomposes the lattice sum into real space and reciprocal space contributions. It also discusses applications of the Ewald summation method, including for uniformly charged surfaces, using fast Fourier transforms to improve computation time, and calculating interactions between molecules.
Research on Transformer Core Vibration under DC Bias Based on Multi-field Cou...inventionjournals
The Mathematical models for DC bias vibration analysis of the transformer core are developed in this paper. The model is combined into multi-physical field coupling modeling for vibration analysis of the transformer. By applying the primary voltage as excitation and under different DC bias, vibrations of the transformer core is simulated and analyzed.
My research at Boston University (May 2013)
1. Thesis: Viscoelastic testing and modeling of PDMS micropillars for cellular force measurement
2. Side Projects
1) Conducting polymer actuators
2) PDMS and conducting polymer nanowire composites
3) Silicon oxycarbide thin films
4) Tribological study of DLC coatings
IRJET- Free Vibration Analysis of BeamsIRJET Journal
The document analyzes the free vibration of beams with different cross-sections, materials, and support conditions. It presents analytical equations based on Euler-Bernoulli beam theory to calculate the natural frequencies of beams. Tables show the fundamental natural frequencies of steel and aluminum beams with circular and rectangular cross-sections in cantilever and simply supported conditions, as calculated analytically and using ANSYS software. The results from both methods show good correlation. Plots of natural frequency versus geometric parameters like diameter and depth are also presented. The study aims to determine the most efficient cross-section and material for structural design by comparing the vibration characteristics.
Efficient mode-matching analysis of 2-D scattering by periodic array of circu...Yong Heui Cho
This document proposes a new mode-matching method for analyzing periodic arrays of circular cylinders with different materials. It uses a common-area concept and infinitesimal perfect magnetic conductor wires to match boundary conditions between rectangular and cylindrical coordinate systems. This allows derivation of scattering equations for the arrays. The solutions are compared to other results to validate the method. It can be used to study resonance characteristics of nanostructures and scattering behavior at different frequencies.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Tomography is important for network design and routing optimization. Prior approaches require either
precise time synchronization or complex cooperation. Furthermore, active tomography consumes explicit
probing resulting in limited scalability. To address the first issue we propose a novel Delay Correlation
Estimation methodology named DCE with no need of synchronization and special cooperation. For the
second issue we develop a passive realization mechanism merely using regular data flow without explicit
bandwidth consumption. Extensive simulations in OMNeT++ are made to evaluate its accuracy where we
show that DCE measurement is highly identical with the true value. Also from test result we find that
mechanism of passive realization is able to achieve both regular data transmission and purpose of
tomography with excellent robustness versus different background traffic and package size.
The International Journal of Engineering and Sciencetheijes
1. The document analyzes the behavior of transmission probability in a single rectangular potential barrier where the barrier height and width are scaled by a common factor such that their product remains constant.
2. Expressions for transmission probability are derived for three cases: particle energy greater than, equal to, and less than the barrier energy. Approximations are used to express transmission probability in terms of the constant barrier height-width product.
3. The results show that transmission probability remains constant for particle energy greater than and less than the barrier energy. However, transmission probability decreases with decreasing particle energy when it is equal to the barrier energy.
The document discusses interference of electromagnetic waves. It explains that the intensity of two waves added together can be calculated using an equation that takes into account the individual intensities, wavelength, and phase difference between the waves. It then provides an example problem where the individual intensities, wavelength, and distance between two waves are given, and calculates the total intensity when the waves are combined using the interference equation.
The document summarizes research determining the optical constants and thickness of tin oxide (SnO2) thin films. Ellipsometry was used to measure the delta and psi values of the thin film coated on a glass substrate. Software analysis of the ellipsometry data found the refractive index of the SnO2 film to be 1.517 and the thickness to be 250 nm. Additional modeling of the complex dielectric function was also discussed to better understand the optical properties of conductive thin films like SnO2.
Vibration Analysis and Modelling of a Cantilever Beam Muhammad Usman
This report in cooperates the techniques, adopted for the evaluation of vibration analysis of a cantilever beam using both techniques i.e. theoretical as well as the practical ones. Computer based analysis of a beam were also performed using Solid Works and Mat Lab software. These techniques helped a lot in finding the natural frequencies and in making the vibrational characteristic behavior of a cantilever beam thus steel used as a material.
Investigation of General Equation That Best Describe the Relationship between...IOSR Journals
This document investigates the general equation that best describes the relationship between survival fraction and critical mass of uranium-235. Monte Carlo simulations were used to study neutron interactions in rectangular uranium-235 geometries. Two models, a cubic equation and logarithmic equation, were tested against observed data from simulations with varying ratios of length to thickness. Statistical analysis showed that the logarithmic equation provided a better fit, with regression values closer to 1. Therefore, the logarithmic equation best describes the relationship between survival fraction and critical mass of uranium-235.
This chapter discusses theoretical models for analyzing piezoelectric fiber composites (PFCs) subjected to push-out and pull-out tests. It presents the basic formulations and assumptions used in the micromechanical model of a single piezoelectric fiber embedded in a polymer matrix. Constitutive equations are provided for the fiber and matrix. Equations are developed relating the stresses and electric fields in the fiber and matrix. Models are then described for analyzing the stress distributions and electric fields in the fiber under both mechanical and electric loads for cases of a perfectly bonded interface and a frictional sliding interface after debonding.
This document summarizes a study that uses the Alternating Direction Implicit Finite-Difference Time-Domain (ADI-FDTD) method to simulate high speed interconnect structures. Specifically, it simulates Coplanar Waveguide (CPW) and Stacked Grounded Coplanar Waveguide (SGCPW) structures to calculate electrical parameters and analyze signal integrity. The ADI-FDTD method is presented and applied to Yee's staggered grid to solve Maxwell's equations without the Courant–Friedrich–Levy stability condition, allowing a larger time step. Numerical simulations compare the CPU run time of ADI-FDTD and standard FDTD for a CPW structure, showing that ADI-FDTD
11.signal integrity analysis of modified coplanar waveguide structure using a...Alexander Decker
This document summarizes a study that uses the Alternating Direction Implicit Finite-Difference Time-Domain (ADI-FDTD) method to simulate high speed interconnect structures. Specifically, it simulates Coplanar Waveguide (CPW) and Stacked Grounded Coplanar Waveguide (SGCPW) structures to calculate electrical parameters and analyze signal integrity. The ADI-FDTD method is presented as an improvement over traditional FDTD as it eliminates constraints on time step size. Simulation results show that ADI-FDTD takes less CPU time than FDTD for analyzing the same structures.
This paper analyses the optimal power system planning with DGs used as real and reactive power compensator. Recently planning of DG placement reactive power compensation are the major problems in distribution system. As the requirement in the power is more the DG placement becomes important. When planned to make the DG placement, cost analysis becomes as a major concern. And if the DGs operate as reactive power compensator it is most helpful in power quality maintenance. So, this paper deals with the optimal power system planning with renewable DGs which can be used as a reactive power compensators. The problem is formulated and solved using popular meta-heuristic techniques called cuckoo search algorithm (CSA) and particle swarm optimization (PSO). the comparative results are presented.
This summary provides an overview of the key points from the document:
1) The document presents the use of General Regression Neural Networks (GRNN) to predict propagation path loss in an urban environment based on measurements taken in Kavala, Greece.
2) Two neural network models are studied - one for path loss prediction and another using error control. Their performance is compared to measured path loss values based on error metrics.
3) For line-of-sight predictions, the GRNN model achieves better performance than empirical models due to using multiple input parameters and generalization. For non-line-of-sight, a third GRNN model including street orientation has the lowest error rates.
This document summarizes research on using particle swarm optimization to reconstruct microwave images of two-dimensional dielectric scatterers. It formulates the inverse scattering problem as an optimization problem to find the dielectric parameter distribution that minimizes the difference between measured and simulated scattered field data. Numerical results show that a particle swarm optimization approach can accurately reconstruct the shape and dielectric properties of a test cylindrical scatterer, with lower background reconstruction error than a genetic algorithm approach. The research demonstrates that particle swarm optimization is a suitable technique for high-dimensional microwave imaging problems.
An Improved Adaptive Multi-Objective Particle Swarm Optimization for Disassem...IJRESJOURNAL
With the development of productivity and the fast growth of the economy, environmental pollution, resource utilization and low product recovery rate have emerged subsequently, so more and more attention has been paid to the recycling and reuse of products. However, since the complexity of disassembly line balancing problem (DLBP) increases with the number of parts in the product, finding the optimal balance is computationally intensive. In order to improve the computational ability of particle swarm optimization (PSO) algorithm in solving DLBP, this paper proposed an improved adaptive multi-objective particle swarm optimization (IAMOPSO) algorithm. Firstly, the evolution factor parameter is introduced to judge the state of evolution using the idea of fuzzy classification and then the feedback information from evolutionary environment is served in adjusting inertia weight, acceleration coefficients dynamically. Finally, a dimensional learning strategy based on information entropy is used in which each learning object is uncertain. The results from testing in using series of instances with different size verify the effect of proposed algorithm.
Expert system design for elastic scattering neutrons optical model using bpnnijcsa
In present paper, a proposed expert system is designed to obtain a trained formulae for the optical model
parameters used in elastic scattering neutrons of light nuclei for (7Li), at energy range between [(1) to
(20)] MeV. A simple algorithm has used to design this expert system, while a multi-layer backwardpropagation
neural network (BPNN) is applied for training and testing the data used in this model. This
group of formulae may get a simple expert system occurring from governing formulae model, and predicts
the critical parameters usually resulted from the complicated computer coding methods. This expert system
may use in nuclear reactions yields in both fission and fusion nature who gives more closely results to the
real model.
Segmentation Based Multilevel Wide Band Compression for SAR Images Using Coif...CSCJournals
Synthetic aperture radar (SAR) data represents a significant resource of information for a large variety of researchers. Thus, there is a strong interest in developing data encoding and decoding algorithms which can obtain higher compression ratios while keeping image quality to an acceptable level. In this work, results of different wavelet-based image compression and segmentation based wavelet image compression are assessed through controlled experiments on synthetic SAR images. The effects of dissimilar wavelet functions, number of decompositions are examined in order to find optimal family for SAR images. The choice of optimal wavelets in segmentation based wavelet image compression is coiflet for low frequency and high frequency component. The results presented here is a good reference for SAR application developers to choose the wavelet families and also it concludes that wavelets transform is rapid, robust and reliable tool for SAR image compression. Numerical results confirm the potency of this approach.
Intelligent fault diagnosis for power distribution systemcomparative studiesnooriasukmaningtyas
Short circuit is one of the most popular types of permanent fault in power distribution system. Thus, fast and accuracy diagnosis of short circuit failure is very important so that the power system works more effectively. In this paper, a newly enhanced support vector machine (SVM) classifier has been investigated to identify ten short-circuit fault types, including single line-toground faults (XG, YG, ZG), line-to-line faults (XY, XZ, YZ), double lineto-ground faults (XYG, XZG, YZG) and three-line faults (XYZ). The performance of this enhanced SVM model has been improved by using three different versions of particle swarm optimization (PSO), namely: classical PSO (C-PSO), time varying acceleration coefficients PSO (T-PSO) and constriction factor PSO (K-PSO). Further, utilizing pseudo-random binary sequence (PRBS)-based time domain reflectometry (TDR) method allows to obtain a reliable dataset for SVM classifier. The experimental results performed on a two-branch distribution line show the most optimal variant of PSO for short fault diagnosis.
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APPLICATION OF PARTICLE SWARM OPTIMIZATION TO MICROWAVE TAPERED MICROSTRIP LINES
1. Computer Science & Engineering: An International Journal (CSEIJ), Vol. 4, No. 1, February 2014
DOI : 10.5121/cseij.2014.4106 59
APPLICATION OF PARTICLE SWARM OPTIMIZATION
TO MICROWAVE TAPERED MICROSTRIP LINES
Ezgi Deniz Ülker1
and Sadık Ülker2
1
Department of Computer Engineering, Girne American University, Girne, Cyprus
2
Department of Electrical and Electronics Engineering, Girne American University,
Girne, Cyprus
ABSTRACT
Application of metaheuristic algorithms has been of continued interest in the field of electrical engineering
because of their powerful features. In this work special design is done for a tapered transmission line used
for matching an arbitrary real load to a 50Ω line. The problem at hand is to match this arbitray load to 50
Ω line using three section tapered transmission line with impedances in decreasing order from the load. So
the problem becomes optimizing an equation with three unknowns with various conditions. The optimized
values are obtained using Particle Swarm Optimization. It can easily be shown that PSO is very strong in
solving this kind of multiobjective optimization problems.
KEYWORDS
Particle Swarm Optimization (PSO), Tapered Microstrip Lines
1. INTRODUCTION
Metaheuristic algorithms have been applied to engineering optimization problems for a long time.
Over the past years an increasing interest for these optimization problems in the field of
microwave engineering has increased substantially. Among these, Particle Swarm Optimization
(PSO) is one of the well known and powerful algorithm. It is a population based swarm algorithm
and proposed by Kennedy and Eberhart [1]. It is inspired by the behavior of swarms such as fish
or birds and found to be very efficient in a wide variety of optimization problems [2,3]. The
potential candidates are called particles and PSO depends on moving particles towards the
optimal solution to the objective function in the search space [4].
The algorithm can update particles and can be optimized using the following control parameters
c1, c2 and w. The term c1 is called cognitive parameter, c2 is the social parameter and ω is called
inertia weight. Vmin and Vmax can be used as constriction parameters that define the maximum and
minimum positions of a particle in the search space. PSO algorithm is a parameter dependent
algorithm. The optimal combination of these parameters enables the PSO to reach the best
solution rapidly [5].
In PSO, possible particles move in the search space to find the global optimum. This movement is
based on proper combinations of control parameters and a replacement formula. Particles also
change their positions using their own position called Pbest (particle best) and swarm’s best
position Gbest (global best). When a better solution is discovered by any particle, all particles
improve their positions to this better solution in the search space.
2. Computer Science & Engineering: An International Journal (CSEIJ), Vol. 4, No. 1, February 2014
60
The flowchart for PSO is given in Figure 1. The main steps of the PSO algorithm are given as
follows:
Step 1. Initialize the particles Xi with initial random positions in search space, and the velocities
of particles Vi in a given range randomly and define these as the best known positions (Pbest) of
each particle.
Step 2. Define the objective function f that needs to be optimized.
Step 3. For each particle calculate the distance to the optimal solution called fitness, and apply
equation (1):
If ibestbesti XPPfXf =< )()( (1)
Step 4. Select globalbest among the Pbest
Step 5. If f(globalbest) reaches to the optimal solution, terminate the algorithm. Otherwise; update
the velocity Vi and the particles Xi according to given equations:
( ) ( )ibestibestii XglobalcXPcVV −⋅+−⋅+⋅= 21 (2)
iii VXX += (3)
Step 6. Go to Step 3, if stopping criteria are not satisfied.
Figure 1: Flowchart of Particle Swarm Optimization [6]
3. Computer Science & Engineering: An International Journal (CSEIJ), Vol. 4, No. 1, February 2014
61
2. MICROWAVE PROBLEM
Matching circuits are the essential elements in microwave circuit design. There can be many
different methods that can be applied depending on many different considerations. Among the
matching circuit types, we can consider shunt stub matching and lumped element matching as
popular techniques if the loads are complex loads.
If the matching load is a real load, quarter wave matching networks can also be used. Tapered
lines are also used in designing matching network circuits. Among the different ones are
Exponential Taper and Klopfenstein Taper [7]. Depending on desired bandwidth in design, proper
design can be made with a sacrifice in return loss. A circuit diagram for a microstrip tapered line
is shown in Figure 2 below.
Figure 2. Microstrip Tapered Line
As we can see in the figure, we can cascade couple of sections of high impedance to lower
impedance transmission lines of quarter wave long, starting from the load impedance to form a
tapered transmission line to achieve matching.
3. EXPERIMENTAL WORK
In this case, problem at hand can be thought as of three section tapered transmission line with
each transmission line having a different impedance value and each being quarter wavelength
long.
The equation that descibes the given problem can be simplified as:
50
100
1
),,(
2
2
31
321 −
⋅
⋅=
Z
ZZ
ZZZf (4)
We try to make the value of above function 0. This is one constraint, the other constraint that we
have is 123 ZZZ << .In order to solve this problem, 100 particles which hold the values of Z1,
Z2 and Z3 were created randomly and the PSO algorithm was applied to obtain the optimum
values of Z1, Z2 and Z3 that minimizes the value of equation (4).
The impedances were kept between 10 Ω and 120 Ω all the time. Also, as mentioned above, the
second criteria was to have the impedances in decreasing order (i.e. the impedance closest to the
4. Computer Science & Engineering: An International Journal (CSEIJ), Vol. 4, No. 1, February 2014
62
load was going to have the highest impedance value). The PSO parameter values were as
follows: social and cognitive parameters were set to 1.8 and inertia weight was set to 0.7. The
particles reached to the optimum values very fast. A sample graph showing this convergence to
optimum values (i.e. obtaining values that satisfy (4)) can be shown in Figure 3.
Figure 3. Sample Convergence Graph
As we can see in the graph, in 100 iterations algorithm converges to a good approximate answer
and within 10000 iterations the answer can be found. Different runs were done and the sample
results are tabulated in Table 1.
Table 1. Obtained Microstrip Impedances from Different Trials
Trial number Fitness value Z1 (Ω) Z2(Ω) Z3(Ω)
Trial 1 0.000002 83.828 79.787 67.302
Trial 2 0.000007 86.427 55.545 45.444
Trial 3 0.00051 76.604 65.646 60.595
Trial 4 0.000034 95.949 76.757 56.567
Trial 5 0.000174 78.77 67.66 60.73
Trial 6 0.000022 90.012 14.131 11.101
Trial 7 0.000009 98.979 28.264 20.191
Trial 8 0.00016 96.435 30.292 22.212
Trial 9 0.000005 80.797 36.922 32.313
From the table we see that fitness values are all very well in almost all the runs at about 1000
iterations. Moreover the impedances are ordered in decreasing order as we desired. For test
purposes the obtained results were simulated using a Microwave Simulator PUFF [8]. For Trial 2
and Trial 3 the responses obtained using the simulator are shown in Figure 4 and Figure 5
respectively.
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
1 10 100 1000 10000
Fitness
Number of Iterations
5. Computer Science & Engineering: An International Journal (CSEIJ), Vol. 4, No. 1, February 2014
63
Figure 4. Reflection Response for Trial 2 tapered design (86.427Ω, 55.545Ω, 45.444Ω)
Figure 5. Reflection Response for Trial 3 tapered design (76.604Ω, 65.646Ω, 60.595Ω)
In both cases desired matching is obtained at 5 GHz. Reflection coefficient value being -100 dB
indicates almost zero reflection and a good match to a 50 Ω transmission line.
4. CONCLUSIONS
In this work, a microstrip tapered transformer design is done using Particle Swarm Optimization.
The problem is a multiobjective optimization problem with an objective function that needs to be
optimized and with a requirement about the elements of the objective function to be in a
decreasing order. The obtained results are verified using PUFF simulator and it can be concluded
that PSO finds the solution to this problem in less than 1000 iterations. Simulated results also
show that results that were obtained give the matching that is desired. Therefore particle swarm
optimization can be very effectively applied for the design of microstrip tapered transformers.
-120
-100
-80
-60
-40
-20
0
0 2 4 6 8 10
ReflectionResponse(dB)
Frequency (GHz)
-120
-100
-80
-60
-40
-20
0
0 2 4 6 8 10
ReflectionResponse(dB)
Frequency (GHz)
6. Computer Science & Engineering: An International Journal (CSEIJ), Vol. 4, No. 1, February 2014
64
REFERENCES
[1] Kennedy J., Eberhart R., (1995) “Particle Swarm Optimization”, ABC Proceedings of IEEE
International Conference Neural Networks, Piscataway NJ, pp. 1942-1948.
[2] Ülker S. (2008) “Particle Swarm Optimization Application to Microwave Circuits,” Microwave
Optical Technology Letters, vol. 50, May 2008, pp. 1333-1336.
[3] Yılmaz A. E., Kuzuoğlu M. (2007) “Calculation of Optimized Parameters of Rectangular Microstrip
Patch Antenna Using Particle Swarm Optimization,” Microwave Optical Technology Letters, vol. 49,
December 2007, pp. 2905-2907.
[4] Shi Y. H., Eberhart R. (1998) “A Modified Particle Swarm Optimizer,” IEEE International
Conference on Evolutionary Computation, Anchorage, Alaska, 1998.
[5] Shi Y. H., Eberhart R. (2000) “Comparing Inertia Weights and Constriction Factors in Particle
Swarm Optimization,” Proceedings of the Congress on Evolutionary Computation, 2000, pp. 84-88.
[6] Kuo R. J., Hong S. Y., Huang Y. C. (2010) “Integration of Particle Swarm Optimization Based
Fuzzy Neural Network and Artificial Neural Network for Supplier Selection,” Applied Mathematical
Modelling, volume 34, issue 12, December 2010, pp. 3976-3990.
[7] Pozar D. M. (2005) Microwave Engineering, 3rd Edition, Wiley, New York, 2005.
[8] Wedge S. W., Compton R. C., Rutledge D. B., Gerstlauer A. (1998) PUFF: Computer Aided Design
for Microwave Integrated Circuits, version 2.1, California Institute of Technology, Pasadena CA
1998.
Authors
Ezgi Deniz Ulker
received the B.Sc., M.Sc., and PhD degree in computer engineering from Girne American
University, Girne, Cyprus, in 2008, 2010 and 2013 respectively. She worked as a teaching
assistant in Girne American University between 2008-2010. She worked as a lecturer in Girne
American University from 2010 till 2013. She has been working as Assistant Professor in
Girne American University since December 2013. Her research interests include optimization
techniques and studying different algorithms and their applications to solve different
optimization and design problems. She authored and coauthored technical publications in the areas of
optimization and metaheuristic algorithms. She is a member of IEEE and IEEE Computer Society.
Sadik Ulker
received the B.Sc., M.E. and Ph.D. degree in electrical engineering from University of
Virginia, Charlottesville, VA, USA, in 1996, 1999, and 2002 respectively. He worked in the
UVA Microwaves and Semiconductor Devices Laboratory between 1996-2001 as a research
assistant. Later he worked in UVA Microwaves Lab as a Research Associate for one year.
He joined Girne American University, Girne, Cyprus in September 2002. He was a member
of electrical and electronics engineering department as an Assistant Professor until 2009. In
2009 he was promoted to Associate Professor status and in 2013 he was promoted to
Professor status in the Electrical and Electronics Engineering Department. He has also been the vice-rector
of the Girne American University responsible from academic affairs since April 2009. His research
interests include Microwave Active Circuits, Microwave Measurement Techniques, Numerical Methods,
and Metaheuristic Algorithms and their applications to design problems. He has authored and coauthored
technical publications in the areas of submillimeter wavelength measurements and particle swarm
optimization technique. He is a member of IEEE and Eta Kappa Nu. He is also the recipient of Louis T.
Rader Chairpersons award in 2001.