List of Articles
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Open Access Article
1 - A New Approach to Compress Multicarrier Phase-Coded Radar Signals
R. mohseni a. sheikhi m.a. masnadi shiraziMulticarrier phase coded signals have been recently introduced to achieve high range resolution in radar systems. As single carrier phase coded radars, the common method for compression of these signals, is using matched filter or computing the auto correlation function MoreMulticarrier phase coded signals have been recently introduced to achieve high range resolution in radar systems. As single carrier phase coded radars, the common method for compression of these signals, is using matched filter or computing the auto correlation function directly. In this paper we propose a new method based on fast Fourier transform (FFT) with lower computational load with respect to traditional approach. Furthermore, based on this new approach, a method for estimation of communication channel is introduced that can be used for improving detection performance and target position estimation in tracking mode. Manuscript profile -
Open Access Article
2 - On the Stability of Primal-Dual Congestion Control Algorithm in the Presence of Exogenous Disturbances
A. moarefianpour V. johari majdIn this paper, we consider the effects of exogenous disturbances on the closed-loop system of the congestion control problem in a network with general structure. This investigation is important since many of data flows in internet network are considered as unmodeled flo MoreIn this paper, we consider the effects of exogenous disturbances on the closed-loop system of the congestion control problem in a network with general structure. This investigation is important since many of data flows in internet network are considered as unmodeled flows. In contrast to previous works, we suppose that both senders and links in the network have dynamics. Each sender updates its sending rate to minimize its own cost function. The network is modeled based on fluid flow approximation with nonlinear dynamics for the links. In this research, we first derive the conditions for the existence of the system equilibrium point taking into account the constraint sets of the problem. Then, we prove input-to-state stability (ISS) of the closed-loop system for the congestion control problem with input and output disturbances in the network links. We further show that the obtain results are valid even when the routing matrix of the network varies. Finally, we verify the theoretical results by simulation on two different multi-link networks. Manuscript profile -
Open Access Article
3 - Design of Low Power High Speed Dilation Operator for Binary Images in CMOS Technology
M. hajirahimi E. KabirThis paper describes the design of hybrid wave-pipeline architecture for implementation of real time morphological dilation. With minor changes to this architecture, it can be utilized for erosion, closing, and opening operators. The new architecture results in higher s MoreThis paper describes the design of hybrid wave-pipeline architecture for implementation of real time morphological dilation. With minor changes to this architecture, it can be utilized for erosion, closing, and opening operators. The new architecture results in higher speed, less hardware complexity, and lower area and power dissipation compared to conventional pipeline implementation. In addition, it is faster than the wave-pipeline structure, without the difficulty of balancing the delay of long signal paths. Using the new architecture, three ASIC chips in 0.18µm CMOS are designed for binary image processing through Verilog. These chips dilate a 1024×1024 image by a 21×21 structuring element in 256.58μ s. The maximum frequency of the operations is 5.882 GHz, 5 GHz, and 4.167 GHz. For the power supply of 1.8 V and the 4.167 GHz frequency, the power dissipation is 597mW, 478 mW, and 410 mW, and the chip area is 0.118 mm2, 0.087 mm2, and 0.075 mm2, respectively. Manuscript profile -
Open Access Article
4 - Design of New TFCS Algorithm for Direction Finding of Multiple Speakers
M. atashbar M. H. KahaeiEstimation of speakers' directions is one of the interesting topics. In this paper, we introduce the TFCS algorithm for direction-of-arrival estimation of multiple speakers. In this algorithm, no limitations are imposed on the environment and speech signals. Simulation MoreEstimation of speakers' directions is one of the interesting topics. In this paper, we introduce the TFCS algorithm for direction-of-arrival estimation of multiple speakers. In this algorithm, no limitations are imposed on the environment and speech signals. Simulation results show that the proposed algorithm outperforms the recently addressed onset and spectral-based methods. Manuscript profile -
Open Access Article
5 - A New Voice Packing Method to Regenerate Lost Packets
Y. darmaniThis article introduces a new voice packing scheme to transfer voice samples over the Internet. This method aims to reduce the voice quality degradation caused by lost packets as far as possible. Regenerating lost voice packets in active nodes in the network, introduces MoreThis article introduces a new voice packing scheme to transfer voice samples over the Internet. This method aims to reduce the voice quality degradation caused by lost packets as far as possible. Regenerating lost voice packets in active nodes in the network, introduces more received voice quality at the receiver side compared with the other methods. This scheme is simulated using an unreliable network with an active node, and it shows more voice quality than the other schemes even if the network loses 50 percent of packets. Manuscript profile -
Open Access Article
6 - Using Adaptive Diffusion Coefficients in Partial Diffusion Equation for Image Noise Reduction
H. hassanpour M. nikpourThis paper proposes a new approach for image noise reduction using partial diffusion equation (PDE). Diffusion coefficient is an important parameter in PDE for image noise reduction. This parameter affects the noise reduction results and quality of edges in the denoised MoreThis paper proposes a new approach for image noise reduction using partial diffusion equation (PDE). Diffusion coefficient is an important parameter in PDE for image noise reduction. This parameter affects the noise reduction results and quality of edges in the denoised image. The existing PDE-based image denoising techniques experimentally adjust the diffusion coefficient. This paper proposes a new approach to adaptively adjust the diffusion coefficient. The proposed approach was applied on a number of standard images to evaluate its performance. The results indicate that the proposed approach outperform the existing PDE-based image denoisng techniques. Manuscript profile -
Open Access Article
7 - The Effect of Demand Response Programs on Iranian Electric Power Consumption
H. alami Gh. yousefi M. Parsa-MoghaddamDemand side management (DSM) is one of the most important methods which have been used to maximize the benefits of the electric power market participants. In the deregulated power systems, DSM is called demand response (DR). In this paper, two DR programs have been focu MoreDemand side management (DSM) is one of the most important methods which have been used to maximize the benefits of the electric power market participants. In the deregulated power systems, DSM is called demand response (DR). In this paper, two DR programs have been focused: time-of-use (TOU) and emergency demand response program (EDRP). In this paper DR is modeled considering both TOU and EDRP methods, simultaneously, using the single and multi period load models, based on the load elasticity concept. The proposed model is implemented on the peak load of the Iranian Power Grid and the optimum prices for TOU program and the optimum incentives for combined TOU and EDRP programs are determined. Manuscript profile -
Open Access Article
8 - A New Combined Strategy for Estimation of Individual Power Quality Parameters Using Adaptive Neural Network
H. R. Mohammadi A. Yazdian Varjani H. mokhtariWith respect to increment of power quality problems and also increasing application of sensitive devices to such problems, the power quality enhancement becomes a serious concern. The series-shunt and combined compensators can be used for compensation of voltage, curren MoreWith respect to increment of power quality problems and also increasing application of sensitive devices to such problems, the power quality enhancement becomes a serious concern. The series-shunt and combined compensators can be used for compensation of voltage, current, or both voltage and current. One of the most important stages for precise and optimized compensation of power quality parameters is the fast and accurate estimation of individual parameters. In this paper, a new combined strategy based on a unified adaptive estimator is proposed which is capable of detection and accurate estimation of individual power quality parameters. In comparison to other estimation methods, the proposed method has a simple structure, low computation, high precision and is capable of individual power quality parameters estimation. Therefore, the proposed method can be used for on-line application such as selective compensation in series, shunt active power filters, and unified power quality conditioner. The exclusive properties of the proposed strategy will be shown by simulation results in transient and steady state conditions. Manuscript profile -
Open Access Article
9 - A Novel Structure for Fault Current Limiterمحدودکننده جريان عيب، راکتور غير فوق هادی، افت ولتاژ، مدار جبرانکننده
M. abapour M. SabahiIn this paper a new structure for fault current limiter is proposed. In proposed structure the superconductor coil is replaced by a copper coil and the losses of copper coil and power electronic devices are compensated by an auxiliary circuit. The results show that the MoreIn this paper a new structure for fault current limiter is proposed. In proposed structure the superconductor coil is replaced by a copper coil and the losses of copper coil and power electronic devices are compensated by an auxiliary circuit. The results show that the proposed structure has less undesired effect on normal operation of system compared with ordinary superconductor type. The main advantageous of proposed structure are no need to superconductor technology and its control-less operation. The analytical analysis and designing characteristics for DC reactor are presented. Also, the simulation and experimental results are presented to show the effectiveness of proposed structure in fault current limitation. Manuscript profile -
Open Access Article
10 - Optimizing OLAP Queries by Mapping Data Cube to Two Dimensional Space
m.k. sohraby Ahmad Abdollahzadeh BarforoushData warehouse and OLAP are essential elements of decision support systems (DSS) and have been studied in database issues extensively. The requirements of decision support systems are different from on-line transactional processing systems. Query optimization and effici MoreData warehouse and OLAP are essential elements of decision support systems (DSS) and have been studied in database issues extensively. The requirements of decision support systems are different from on-line transactional processing systems. Query optimization and efficient data cube computation have primary roles in improving functionality of DSS. This paper presents a new method for query processing in data warehouses and computing data cubes using bottom-up cube computation techniques. Results of implementation show that the proposed algorithm outperforms two best known algorithms (based on time criterion), and is much faster than them in answering to monotonic query with large volume of data. Furthermore, 2-dimensional view of ex-cube and transforming the data cube to a hyper graph structure, reduce the required space of the algorithm when we aggregate subsets of cube's dimension. Manuscript profile