Showing papers by "Graduate University of Advanced Technology published in 2012"

Fabrication of Al/Cup composite by accumulative roll bonding process and investigation of mechanical properties

Abstract: In the present work, accumulative roll bonding (ARB) process was used to produce Al/Cup composite using Al 1100 strips and Cu fine particles. Microstructure and mechanical properties of the composites were studied during various ARB cycles by scanning electron microscopy (SEM), tensile test and the Vickers micro-hardness test. The SEM results revealed that, as the ARB cycle increases the layer of Cu particles is broken which leads to generation of elongated dense Cu clusters. At higher strains, the size of elongated clusters reduces while their uniformity and sphericity increase. This microstructure changes leads to improving the hardness, strength and elongation during ARB process. Generally, the mechanical properties of Al/Cup composite are better than those of pure Al at the same cycle of ARB. The results also demonstrated that, the Cu reinforcement particles in the form of uniformly dispersed clusters improve simultaneously the strength and toughness of Al during the ARB process.

Optimizing cluster-head selection in Wireless Sensor Networks using Genetic Algorithm and Harmony Search Algorithm

Abstract: Being an important factor in designing Wireless Sensor Networks, network lifetime depends on the energy of the sensor nodes which is limited by the battery of the node. Clustering is considered to be an energy management strategy in wireless sensor networks, and Leach is one of the most well-known clustering mechanisms. Random cluster selection in this method has lead to its inefficiency. In this paper we proposed two algorithms, GP-Leach and HS-Leach. We improved the energy consumption by partitioning the network and using the evolutionary algorithms for optimized cluster head selection considering WSN nodes' position information and residual energy. The simulation results performed in MATLAB shows that our proposed algorithms are more efficient and they increased the lifetime of the network.

A simple approach to static analysis of tall buildings with a combined tube-in-tube and outrigger-belt truss system subjected to lateral loading

Abstract: In this paper, an efficient technique is presented for static analysis of tall buildings with combined tube-in-tube and outrigger-belt truss system while considering shear lag effects. In the process of replacing the discrete structure with an elastically equivalent continuous one, the structure is modeled as two parallel cantilevered flexural-shear beams that are constrained at the outrigger-belt truss location by a rotational spring. Based on the principle of minimum total potential energy, simple closed form solutions are derived for stress and displacement distributions. Standard load cases, including uniformly distributed loads, triangularly distributed loads and point loads at top of the structure are considered. Results obtained from the proposed method for 50 and 60 story tall buildings are compared to those obtained using a standard finite element computer package. The approximate analyses are found to yield reasonable results and give a fairly good indication of actual structure’s response.. doi: 10.5829/idosi.ije.2012.25.03a.10

Optimal Slope-Angles to Determine Maximum Solar Energy Gain for Solar Collectors Used in Iran

Abstract: The aim of this paper is providing atlases to determine maximum solar energy gain and optimum slope angle of solar collectors for Iran. To achieve this purpose, first, the daily, monthly, seasonally and yearly optimum slope and azimuth angles of solar collectors are determined for 30 Iranian cities and the gain of energy is calculated in the mentioned conditions. Then, the atlas of the optimum slope angle and the contour atlas of the maximum energy gain is provided. The Geographic Information System (GIS) is used to outline the maps. These atlases are essentials tools to find the best location for constructing different solar systems. The results show that the energy gain of the collector when it is adjusted at the daily optimum slope angle is almost the same compared with the case at the monthly optimum slope angle. Therefore, the map is provided for the energy gain when the collectors are mounted at the monthly optimum slope angle. The map of optimum slope angle is outlined for the fixed collector used for the entire year due to the high use of fixed collectors. Furthermore, the results show that Iran can be divided into five zone and the areas with the same latitude and climate have almost the same optimum slope angle.

Spectrum allocation based on Artificial Bee Colony in Cognitive Radio networks

Abstract: Cognitive Radio (CR) has been regarded as a promising technology to improve the spectrum utilization significantly. One of the considered issues in CR is the allocation of frequency channels between its users. In this paper, at first, the model is presented, second, new spectrum assignment methods based on Artificial Bee Colony (ABC) algorithm is proposed. In this algorithm in order to decrease the search space is proposed a mapping process between the channel assignment matrix and the position of the bees of ABC based on the characteristics of the channel availability and the interference constraints. The Results show our proposed method has results mush near to the optimal values, which are calculated using exhaustive search. Corresponding results show that our proposed method fast converge in maximizing three objective functions which are: Max-Sum-Reward (MSR), Max-Min-Reward (MMR), and Max-Proportional-Fair (MPF); this feature makes our proposed method useful for practical applications.

Bardsir network reconfiguration using Graph Theory-based Binary Genetic Algorithm to reduce loss and improve voltage profile

Abstract: The purpose of optimal reconfiguration of a distribution network is a matter of finding the best topology of the network to achieve the considered goals. This paper presents an algorithm for optimal reconfiguration of distribution networks using Binary Genetic Algorithm (BGA) based on Graph Theory (GT) as a multi-objective optimization problem. The objective function considers the real power losses, and the network voltage deviation index. Also, lines and transformers loading limits are considered as constraints in the optimization problem. To assess the capabilities of the proposed approach, two networks are studied: the IEEE 33-bus distribution network as a small grid and Bardsir regional medium voltage distribution network as a large-scale grid. Simulation results show both voltage profile improvement and loss reduction compared to the situation before the reconfiguration. The algorithm is implemented in MATLAB software and then evaluated by DIgSILENT Power Facrory 14.0.515 software.

Forest fire hazard modeling using hybrid AHP and fuzzy AHP methods using MODIS sensor

Abstract: Forest fire is one of the major natural risks in the north of Iran. It is impossible to control nature, but is possible to map forest fire risk zone and thereby minimize the risk of fire. The aim of this study is modeling the potential of forest fire in the Golestan forests by using Remote Sensing, GIS and aerologic data. The variables in this study must be weighted according to their impact on the forest fire hazard. Therefore analytical hierarchy process (AHP), and fuzzy-AHP, used to rank and prioritize the causative factors of fire risk in the study area. Fires occurred at 2010 in this zone and using the MODIS fire product dataset shown that majority of burned area were in the recommended risky places of this model by overall accuracy about 64%. Finally the sensitivity analysis applied to model wherein shown the fuel has highest degree of sensitivity.

Static deflection analysis of flexural rectangular micro-plate using higher continuity finite-element method

Abstract: In this paper, strain gradient theory is used in developing a mathematical model based on classical flexural Kirchhoff plate theory that can predict static response of rectangular micro-plates. The result of this new model is a sixth order differential equation. Order of differential terms in Galerkin weak form of the equation is reduced so that C 2 hierarchical p -version finite elements with second order global smoothness can be used to solve the problem. With different boundary conditions, the computed deflection distribution of micro-plates is compared with those of the classical theory, in which length scale parameters are not present. A series of studies have revealed that when length scale parameters are considered, deflection of a rectangular plate decreases with increasing the length scale effect; in other words micro plates exhibit more rigidity than what is predicted by the classic model. Here, deflections are normalized with respect to results obtained from classical plate theory. Comparison of maximum deflection values obtained from the extended model for micro plates with those available from the classic plate model indicates that classical theory overestimates displacement values and the largest error is observed for square micro plates. The overestimation levels off for plates with aspect ratios greater than three.

Optimal placement and determine parking capacity of electric vehicles to improve VSM and congestion

Abstract: Nowadays, Electric vehicle parking (EVP) can be used as a distributed generation (DG) as an important opportunity. EVP is different with other DGs and can be used as a load or supplier, so it helps to flatten the grid load curve. Based on this matter optimal placement of EVP is an important matter. In this paper an optimal placement problem with considering multi-objective optimization is defined. Solving this problem, causes to improve some objects i.e. congestion, Voltage security margin (VSM), cost and voltage stability. To solve modeled optimization problem, an Elitist genetic algorithm optimization has been developed. This algorithm consists of continuous and discrete sections, so in addition placement, the optimal capacity of the selected parking can be calculated. These results have been analyzed and evaluated in different conditions and modified IEEE 14-bus and 30-bus networks are used as cases study.

Comparison of multiple linear regression, partial least squares and artificial neural network for quantitative structure retention relationships of some polycyclic aromatic hydrocarbons

Abstract: Quantitative structural-retention relationships (QSRR) of retention phenomena of polycyclic aromatic hydrocarbons (PAHs) facilitate resolving complex mixtures of them by gas chromatography (GC). The structural descriptors of 38 PAH compounds were calculated. Stepwise variable selection was applied for selection of meaningful descriptors. MLR, PLS and ANN models were built with calibration compounds. The predictive ability of the models was evaluated on 6 PAHs, which were not used in training steps and also by leave-6-out cross-validation. The best prediction results were obtained by the MLR model. The difference in predictive ability of the ANN and PLS model was trivial.

An efficient algorithm for human cell detection in electron microscope images based on cluster analysis and vector quantization techniques

Abstract: Automatic detection of human cell is one of the most common investigation methods that may be used as part of a computer aided medical decision making system. In this paper we present an efficient algorithm, based on the cluster analysis and the vector quantization techniques for human cell image detection. First, we perform the edge detection methods to specify the desired region of any object in image and then apply vector quantization technique to cluster the property approximation of human cells. Our proposed algorithm is applied on two sample datasets from our research laboratory and also Imamreza laboratory in Mashhad which contain 196 number of normal electron microscope images. Experimental results show that this model is both accurate and fast with a detection rate of around 86.69 percent. Our proposed method does not require any under segmentation.

Human cardiac troponin I sensor based on silver nanoparticle doped microsphere resonator

Abstract: Human cardiac troponin I (cTnI) is a specific biomarker for diagnosis of acute myocardial infarction (AMI) In this paper, a composite sensing system of an optical microsphere resonator and silver nanoparticles based on surface enhanced Raman scattering (SERS) and stimulated Raman scattering (SRS) techniques towards a point of care diagnostic system for AMI using the cTnI biomarker in HEPES buffered solution (HBS) is proposed Pump and Raman signals enter the optical fiber coupling into the microsphere, and then SRS occurs in the microsphere The presence of silver nanoparticles on the microsphere surface provides a tremendous enhancement of the resulting Raman signal through an electromagnetic enhancement of both the laser excitation and Stokes-shifted light of the order of 1010 This enhancement occurs in metals as surface plasmon resonance (SPR), which increases the Raman gain through the SERS effect Our simulation results show that this sensor presents a linear response for cTnI detection The calculated enhanced Raman signal can be employed to detect the cTnI molecules around the microsphere

Parameterization of 241Am and 230Th alpha particle energy in dependence on distance traveled in air

Abstract: A new method is introduced in this paper for calculating alpha particle energy versus traveled distance (APETD) in air as emitted from 241Am and 230Th sources as well as the alpha range versus its energy and its energy versus distance. This method is to derive the stated relevant equations and in particular to speed up the calculation of E(x) by a Monte-Carlo simulation. By a fitting procedure, an analytical formula E(x) was determined in terms of a series of powers of distance x. Then a randomly sampled x can be quickly transformed into a corresponding energy E. The APETD calculations were run on a Microsoft Windows 7 32 bit operating system with a maximum usable memory of 3 GB. The results of calculations for alphas of the above two radionuclides in air compared to those of others using a different method are in good agreement. The above stated equations as derived in this paper are presented and the process time for applying the new method has been greatly improved.

Application of multi-way partial least squares calibration for simultaneous determination of radioisotopes by liquid scintillation technique

Abstract: Three-way partial last squares (3-PLS2), as a multi-way calibration method was applied for determining the 235U/238U isotope ratio to overcome problems with spectral interferences in liquid scintillation spectra of these radioisotopes. The alpha energy spectra of samples in different energy channels and different cocktail to sample ratios were used as input data for 3-PLS2. The model was applied to a prediction set and satisfactory results were obtained. The 3-way PLS2 prediction results were compared with 2-way PLS2 and it was shown that 3-way PLS2 results are more accurate than the results of PLS2. Thermal ionization-mass spectrometry was used as a reference method for calculating the accuracy of our method.

Survey on network access control technology in MANETs

Abstract: Using Mobile Ad hoc Networks (MANETs) is growing with advances in technology. MANETs consist of few nodes with constrict resources and without any special structure. Each node can be connected to other nodes in its own transition rate. Network access control with respect to the development of networks is very important. In this paper, we explain the Network Access Control (NAC), the mechanism of action in the networks and also compare some NAC vendors. We briefly describe four network access control protocols for MANET and also compare them in terms of efficiency, communication complexity, overhead, and the techniques which is used. In the other part we describe the attacks in MANETs.

Transmission and generation expansion planning considering loadability limit using game theory & ANN

Abstract: Transmission and generation expansion planning (TEP and GEP) considering loadability limit of power system is studied in this paper. Artificial neural network (ANN) technique is used to evaluate loadability limit of the power system because of its sensitivity characteristic. Power system restructuring and separation of decision-making organizations of transmission and generation expansion, make coordination between generation and transmission companies more crucial. On the other hand, voltage stability is one of the indicators of power system security level. In this paper, first the load pattern of a six-bus power system is improved and then the best bus for load increment is determined using sensitivity characteristic of ANN. Afterwards the strategic interaction between transmission company (TransCo) and generation company (GenCo) for TEP and GEP in a competitive electricity market is proposed using Game Theory (GT). The proposed algorithm comprises three optimization levels to determine Nash equilibrium such that the most profitable strategy for both sides of the game can be found out in an expansion planning game.

Calculating CR-39 Response to Radon in Water Using Monte Carlo Simulation

Abstract: Introduction CR-39 detectors are widely used for Radon and progeny measurement in the air. In this paper, using the Monte Carlo simulation, the possibility of using the CR-39 for direct measurement of Radon and progeny in water is investigated. Materials and Methods Assuming the random position and angle of alpha particle emitted by Radon and progeny, alpha energy and angular spectrum that arrive at CR-39, the calibration factor, and the suitable depth of chemical etching of CR-39 in air and water was calculated. In this simulation, a range of data were obtained from SRIM2008 software. Results Calibration factor of CR-39 in water is calculated as 6.6 (kBq.d/m)/(track/cm) that is corresponding with EPA standard level of Radon concentration in water (10-11 kBq/m). With replacing the skin instead of CR39, the volume affected by Radon and progeny was determined to be 2.51 mm for one m of skin area. The annual dose conversion factor for Radon and progeny was calculated to be between 8.8-58.8 nSv/(Bq.h/m). Conclusion Using the CR-39 for Radon measurement in water can be beneficial. The annual dose conversion factor for Radon and progeny was calculated to be between 8.8-58.8 nSv/ (Bq.h/m).

Polarization of Lyman-α and Balmer-α emission in proton-hydrogen collisions: a study using first-order Born-Faddeev-type equations

Abstract: A three-body Born‐Faddeev model is devised to calculate the total cross sections of Balmer-α and Lyman-α emissions, for the excitation of hydrogen atoms by proton impact in the energy range of 100 keV‐7 MeV. In addition, the polarization alignment factor A20 is calculated and compared against available experimental data to further test the theory. Specifically, here we use the Faddeev‐Watson‐Lovelace formalism to study the excitation of atomic hydrogen from its ground state to the excited states of n = 2 and 3 and magnetic sublevels l = 0, 1 and 2, wherever applicable. The first-order electronic, A (1) e , and the first-order nuclear, A (1) n , amplitudes are considered in order to calculate the excitation transition matrix (TPT), while a near-the-shell condition is assumed throughout. In addition, our results were used to calculate the first-order form factors. The present results are compared, where possible, with those of other theoretical and experimental works that are currently available in the literature.

Providing QoS guarantee of timeliness in wireless sensor networks with a new routing methodology

Abstract: Wide spread use of wireless sensor networks (WSNs) in critical applications shows the importance of Quality of service (QoS) in these networks. Timeliness is one of the QoS parameters which has great importance in real time applications such as earthquake detection. Several geographic routing protocols have been proposed for WSNs which provide QoS support in timeliness domain. Most of these protocols use one-hop neighborhood information to make routing decisions. Timeliness can be improved by using multi-hop neighborhood information which increases control overhead and decreases network lifetime. In other words, the choice of two-hop neighborhood information is a tradeoff between timeliness and control overhead. In this paper, we propose a QoS-aware routing protocol, called Maximum Speed Routing Protocol (MSRP) for WSNs to provide QoS-guarantee in timeliness domain. MSRP is based on two-hop neighborhood information with low control overhead and it can improve timeliness by sending packets with maximum speed across the network. Also, MSRP considers the distance between a neighbor and destination to determine next forwarding node and uses a different method to estimate delay between two neighbors. Simulation results show that MSRP improves performance in terms of end-to-end delay, delivery ratio and hop counts.

A low voltage current-bleeding down-conversion folded mixer

Abstract: This paper presents an ultra low voltage down conversion CMOS mixer. To facilitate low-voltage operation, the mixer employs a folded Gilbert cell topology with PMOS devices for LO switches. The folded topology allows the transconductance and LO stages to have different bias current. Current bleeding technique has been used to improve the conversion gain, NF and the linearity due to the higher RF stage bias current without varying the switching transistors current. Inductive peaking technique is also used to succeed extension bandwide. A comparison with conventional down-conversion mixers shows that this mixer has advantages of simultaneous low-voltage and high performance. The mixer is simulated using 0.13-μm CMOS process model by advanced design system (ADS) tool and results show that under 0.7V supply, a flatness conversion gain 7.9+1 dB, a single-sideband (SSB) noise figure (NF) of 5–14.1 dB, an input third-order intercept point (IIP3) of 6.8dBm and 1-dB compression point of −1.9dBm between 0.5–10GHz.

Feature extraction of hyperspectral images based on reformulate computation of between class scatter matrixes

Abstract: This paper proposes a method called Adjusted Linear Discriminant Analysis (ALDA) for feature extraction of hyperspectral remote sensing imagery. In this method the variances of the classes are considered as a weight to estimate between-class scattering matrix appropriately. Experimental results on well known hyperspectral dataset demonstrate that compared to conventional LDA based feature extraction algorithms the overall accuracy of the classification increased.

A 0.7-to-1.1-GHz all-digital phase-locked loop with a new phase frequency detector and controlled oscillator with body-biasing

Abstract: A 0.7-to-1.1-GHz all-digital phase locked loop with a new phase frequency detector and controlled oscillator with body-biasing is presented. Digital-to-voltage converter is controlled the bulk voltage in proposed voltage controlled oscillator, which results high frequency resolution and low power consumption. A search algorithm is used to generates the digital code for the digital-to-voltage converter. This all-digital phase locked loop uses a new structure for the phase-frequency-detector, which ensures high accuracy at phase frequency detecting and increasing lock speed. The proposed design is evaluated in PTM 65nm. The power consumption of the proposed circuit at 900 MHz frequency is 4.8mW.

Approximated Solutions to Operator Equations based on the Frame Bounds

Abstract: We want to find the solution of the problem ${\L} u = f$, based on knowledge of frames. Where ${\L} : H \to H$ is a boundedly invertible and symmetric operator on a separable Hilbert space $H$. Inverting the operator can be complicated if the dimension of $H$ is large. Another option is to use an algorithm to obtain approximations of the solution. We will organize an algorithm in order to find approximated solution of the problem depends on the knowledge of some frame bounds and the guaranteed speed of convergence also depends on them.

Differential cross section for positron formation in Positron - molecular hydrogen ion

Abstract: The present work deals with the study of positronium formation from diatomic molecular ion targets by the impact of energetic positron. The high and intermediate energy positron scattering are considered using corrected boundary conditions method. The transfer of an electron from a molecule by a fast positron is considered assuming an effective one electron model. The results are presented as differential cross sections.

Approximate Identities on Non-Euclidean Manifolds

Abstract: We define a convolution and present a theory for approximate identity on the non-Euclidean manifolds. Here we focus on the hyperboloid and sphere.

Prediction of influence of doping of NaNO 3 on the solid phase thermal decomposition of bitumen using neural networks

Abstract: This study presents an application of artificial neural networks (ANN) for the prediction of the thermal stability of solidified NaNO3 salts in bitumen has been investigated for safety considerations in the field of solidification of radioactive waste. The thermal decomposition of bitumen in presence of NaNO3 in a temperature range 22.650°C has been used. The proposed ANN model uses the NaNO3 concentration and temperature (°C). In this research data's are modelled and analyzed by Multi Layer Perceptron network (MLP). Predictions made by this method are compared with real data's. The results of parametric analyses were used to evaluate Mass loss of bitumen in a quite well manner. It can be concluded that MLP predictions are compatible with the actual data and they yield acceptable predictions.

Application of Haar multi-resolution analysis in subspace V2 to calculate Faddeev partial amplitudes of electron transfer in three-body proton-hydrogen scattering

Abstract: The exact or projected form of the off-the-energy-shell Coulomb transition matrix (T-matrix), in the Daubechies first scalet basis, is used to calculate the Faddeev–Watson–Lovelace (FWL) amplitudes up to the second order, in the electron capture channel for the scattering of high-energy protons by atomic hydrogen. The phase, angular and energy dependence of the FWL partial amplitudes and differential cross sections are constructed. An analytical expression for the differential cross sections is presented as a function of energy and scattering angle. Finally, differential cross sections obtained by the exact and approximate Coulomb off-the-energy-shell T-matrix are compared with the available experimental results.

Pantic b-spline wavelets and their application for solving linear integral equations

Abstract: In this work we deal with the question: how can one improve the approximation level for some nonlinear integral equations? Good candidates for this aim are semi orthogonal B-spline scaling functions and their duals. Although there are different works in this area, only B-spline of degree at most 2 are used for this approximation. Here we compute B-spline scaling functions of degree 4 and their duals, then we will show that, by using them, one can have better approximation results for the solution of integral equations in comparison with less degrees or other kinds of scaling functions. Some numerical examples show their attractiveness and usefulness.

Abstract convexity of extended real valued increasing and radiant functions

Abstract: In this paper, we first investigate abstract convexity of non-negative increasing and radiant (IR) functions over a topological vector space X. We also characterize the essential results of abstract convexity such as support set, subdifferential set and polarity of this class of functions. Finally, we examine abstract convexity, polarity and subdifferential of extended real valued increasing and radiant functions.