In this paper we propose a new approach to reconstruct the three-dimensional model of object using multi camera silhouettes during time. The main idea in this work is to reduce the current bottlenecks of three-dimensional model reconstruction including: ambiguous stereo More
In this paper we propose a new approach to reconstruct the three-dimensional model of object using multi camera silhouettes during time. The main idea in this work is to reduce the current bottlenecks of three-dimensional model reconstruction including: ambiguous stereo matching in low contrast regions; non-exact color adjustment between cameras which raises the matching uncertainty; shading and non-consistency of intensity duo to motion and varying the light angle which raises the motion estimation error; high dependency of silhouette method to the number of cameras. We propose a novel scheme to combine three popular methods i.e. stereo matching, motion and silhouette. The novelties of this work include: region growing for low color different neighborhood to increase the quality of background removing process, robust feature based stereo matching of multi camera images to find the exact place of some sparse singular points belong to the surface of object, singular points matching to robustly estimate the motion parameters in next frame. Also, we propose a hierarchical cone intersection method to extract the bounding edges visual hull from all the silhouettes captured by virtual cameras during time.
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This paper, presents a new approach for bidding strategy in spot electricity markets. A two-level optimization method is used for profit maximization of non-cooperative firms, while taking into account overall system constrains. In this approach, the market equilibrium More
This paper, presents a new approach for bidding strategy in spot electricity markets. A two-level optimization method is used for profit maximization of non-cooperative firms, while taking into account overall system constrains. In this approach, the market equilibrium points are determined as Nash Equilibria. In order to capture the behavior of all market participants and therefore, a much more competitive environment both the suppliers and consumers are considered as the players of the market. To avoid local maxima solutions, Genetic Algorithm based optimization is incorporated. The proposed method has been applied to IEEE 9 bus system with satisfactory results.
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In this paper, an online signature verification method using extended regression in stationary wavelet domain is presented. To calculate the similarity between two signatures by extended regression, we should equalize the time length of the corresponding signals in two More
In this paper, an online signature verification method using extended regression in stationary wavelet domain is presented. To calculate the similarity between two signatures by extended regression, we should equalize the time length of the corresponding signals in two signatures. Using all points of the signals to equalize their time length will decrease the difference between a genuine signature and its forgery. Here a new approach based on the extreme points warping of the signals is presented. This approach equalizes the time length of two signals without degrading the differences between them. Also we calculated the similarity of signatures by using the details of the signals in stationary wavelet transform, SWT, domain, which showed very good results.
The proposed system was tested on SVC2004 signature database. The results were compared with the results of participant teams in the first international signature verification competition. We have gained EER=6% for skilled forgery signatures. Comparing the result, it shows that we stand in the second rank between all the participants. This system has no verification error for random forgery signatures and stands in the first rank. Our experimental results show that using SWT domain instead of time domain decreases the verification error rate by 35%.
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In this paper a novel direct torque control algorithm based on switching table using three-level diode clamp inverter is introduced. Voltage deviation of DC link capacitors is one of the most significant problems of NPC three-level voltage source inverters. The voltage More
In this paper a novel direct torque control algorithm based on switching table using three-level diode clamp inverter is introduced. Voltage deviation of DC link capacitors is one of the most significant problems of NPC three-level voltage source inverters. The voltage imbalance of DC link capacitors will result in low level harmonics, undesirable torque variation and motor efficiency reduction. To resolve this problem, a closed loop algorithm is introduced in this paper, in addition to its simple implementation; the algorithm is able to control the voltage fluctuation of DC link capacitors within the desirable limits. The result of simulation and experimental implementation confirms the performance of this method despite capacitors reduced capacity.
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Solar panels exhibit non-linear current–voltage characteristics producing maximum power at only one particular operating point. The maximum power point changes with temperature and light intensity variations. Different methods have been introduced for tracking the maxim More
Solar panels exhibit non-linear current–voltage characteristics producing maximum power at only one particular operating point. The maximum power point changes with temperature and light intensity variations. Different methods have been introduced for tracking the maximum power point based on offline and online methods. In this paper a new method is presented to improve the performance of maximum power point tracking in off-grid solar panels. The proposed algorithm is a combination of two loops, set point calculation and fine tuning loops. First the set point loop approximates the maximum power using offline calculation of the open circuit voltage. The exact amount of the maximum power will, then, be tracked by the fine tuning loop which is based on perturbation and observation (P&O) method. The proposed method is simulated in Matlab/Simulink environment and experimentally verified using a laboratory prototype. In maximum power point tracking, the effects of frequency variation and disturbance amplitude on dynamic response and steady state performance are examined. Simulation and experimental results are compared with other methods and the effectiveness of the proposed method is evaluated.
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In recent years, solar energy has gained a great deal of attention. Hence, the photovoltaic (PV) systems which convert the solar energy into electricity should achieve high efficiency, low manufacturing cost, and high quality of electric power to attract the consumers. More
In recent years, solar energy has gained a great deal of attention. Hence, the photovoltaic (PV) systems which convert the solar energy into electricity should achieve high efficiency, low manufacturing cost, and high quality of electric power to attract the consumers. Although Cascaded H-Bride (CHB) inverter is a suitable choice for injection of PV power into grid, its control issues have not been completely solved. One of the main challenges in CHB inverter is low margin of stability when the H-bridge cells are under imbalance operating conditions. In this paper, a new MPPT algorithm is proposed for a CHB photovoltaic inverter. The proposed approach not only tracks the maximum point of distinct PV arrays under symmetric insolation, but also behaves well under asymmetric insolation conditions. The latter is achieved through shifting the operating point of PV arrays and using the modulation index of H-bridge cells as a degree of freedom. The usefulness and validity of new method is confirmed by simulation and experiments on a 7-level CHB photovoltaic inverter.
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Separating colored point sets is an interesting problem in computational geometry with application in machine learning and pattern recognition. In this problem, we are given a geometric shape C and two point sets P and Q of total size n as red and blue points, respectiv More
Separating colored point sets is an interesting problem in computational geometry with application in machine learning and pattern recognition. In this problem, we are given a geometric shape C and two point sets P and Q of total size n as red and blue points, respectively. Now, we must separate red and blue points by this shape such that all the blue points lie inside it and all the red points lie outside it. In the previous work, we have some algorithms for rectangle and wedge separability but we do not have any algorithm for separating by a triangle and separating by a triangle with a fixed angle such as right triangle. In this paper, we present an efficient algorithm for right triangle seprability. In this algorithm, we use sweep line technique and introduce some events and process them. So, we can report all separating right triangles in O(nlog n) time.
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Many conventional incremental conductance (INC) methods are applied for maximum power point tracking (MPPT) of photovoltaic arrays. Where, the optimization step size determines the speed of MPPT. Fast tracking could be achieved with bigger increments but the system migh More
Many conventional incremental conductance (INC) methods are applied for maximum power point tracking (MPPT) of photovoltaic arrays. Where, the optimization step size determines the speed of MPPT. Fast tracking could be achieved with bigger increments but the system might not operate properly at the MPP and might become oscillated at this point; therefore, there is a trade-off between the time needed to reach the MPP and the oscillation error. This article is to present an adaptive optimization step size in the INC to improve solar array performance. To adjust the MPP in the photovoltaic (PV) operation point, brain emotional learning based intelligent controller (BELBIC) is applied as an adaptive optimization step size in the INC. This would considerably increase the system's accuracy. The effectiveness of this proposed method is verified by comparing its simulation and experimental results with the conventional methods in different operating conditions.
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In this paper a new topology of three-level inverters with ten-switch is proposed to control low voltage three phase induction motor. Ten-switch inverter is a reduced-switch-count three level inverter which compared to conventional topologies such as NPC, CHB and flying More
In this paper a new topology of three-level inverters with ten-switch is proposed to control low voltage three phase induction motor. Ten-switch inverter is a reduced-switch-count three level inverter which compared to conventional topologies such as NPC, CHB and flying capacitor has lower count of semiconductor switches. Thus, it enjoys from lower cost, lower volume and lower weight. In this paper, a direct torque control (DTC) scheme based on switching table is developed to control a ten switch inverter. Simulation results of controlling induction motor fed by a conventional two-level inverter, NPC and proposed 10 switch inverter are presented and they are compared together in different aspects. Results confirm the effectiveness of the proposed topology and its control method.
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The point-set covering is one of the important problems in computational geometry, which has many applications. In this problem, the given points should be covered by at least one geometric shape. A variant of the problem is the point-set separation, in which there are More
The point-set covering is one of the important problems in computational geometry, which has many applications. In this problem, the given points should be covered by at least one geometric shape. A variant of the problem is the point-set separation, in which there are at least two different kinds of points which are colored by different colors. The geometric shapes, which are called separators, should only cover the points of the same color. In this paper, separation of blue and red points by a double-wedge of a given angle θ is considered. The proposed algorithm reports all separator θ angle double-wedges in optimal time O(nlogn).
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The rapid growth of Location-based Social Networks (LBSNs) is a great opportunity to provide personalized recommendation services. An important task to recommend an accurate Point-of-Interests (POIs) to users, given the challenges of rich contexts and data sparsity, is More
The rapid growth of Location-based Social Networks (LBSNs) is a great opportunity to provide personalized recommendation services. An important task to recommend an accurate Point-of-Interests (POIs) to users, given the challenges of rich contexts and data sparsity, is to investigate numerous significant traits of users and POIs. In this work, a novel method is presented for POI recommendation to develop the accurate sequence of top-k POIs to users, which is a combination of convolutional neural network, clustering and friendship. To discover the likeness, we use the mean-shift clustering method and only consider the influence of the most similarities in pattern’s friendship, which has the greatest psychological and behavioral impact rather than all user’s friendship. The new framework of a convolutional neural network with 10 layers can predict the next suitable venues and then select the accurate places based on the shortest distance from the similar friend behavior pattern. This approach is appraised on two LBSN datasets, and the experimental results represent that our strategy has significant improvements over the state-of-the-art techniques for POI recommendation.
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Doze and sleep mechanisms are the most common energy-saving solution in GPON networks. Sleep duration is the critical value in the energy-saving domain, and it will affect the QoS metrics with inappropriate value. In this paper, a new energy-saving mechanism is proposed More
Doze and sleep mechanisms are the most common energy-saving solution in GPON networks. Sleep duration is the critical value in the energy-saving domain, and it will affect the QoS metrics with inappropriate value. In this paper, a new energy-saving mechanism is proposed using an optimal point based on gradient descent that calculates sleep duration and keeps QoS metrics acceptable. The historical value of average delay and packet, drop ratio, ONU buffer, and bandwidth request parameters are used as input, and the sleep duration value is calculated. The simulation results show that the proposed method saves up to 17% energy in GPON and keeps the network’s QoS in an acceptable domain.
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