Original Research Paper
Network Security
M. Amiri; A. Barati
Abstract
Background and Objectives: Increasing usage of Internet and computer networks by individuals and organizations and also attackers’ usage of new methods and tools in an attempt to endanger network security, have led to the emergence of a wide range of threats to networks.Methods: A honeypot is one ...
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Background and Objectives: Increasing usage of Internet and computer networks by individuals and organizations and also attackers’ usage of new methods and tools in an attempt to endanger network security, have led to the emergence of a wide range of threats to networks.Methods: A honeypot is one of the basic techniques employed for network security improvement. It is basically designed to be attacked so as to get the attackers’ information and trap them. By using a vulnerable scanner in this paper, we obtained the required network vulnerabilities and normalized them via the proposed method. Then, a dynamic hybrid honeypot has proposed by high and low interaction honeypots. Also, in the proposed method, by footprinting and scanning of an integrated network, a detailed picture of the production network and a honeypot configuration file are generated.Results: As a result, more devices could be detected via automated production by the proposed method.Conclusion: This method could accelerate honeypot production and reduce the users’ mistakes during their manual production. Monitoring network traffic, collecting the information of network machines, determining network operating systems, and storing data in a database are the specific features of this system that could be performed by using the selected network scanning tools and modules.
Original Research Paper
Control
H. Chenarani; M.M. Fateh
Abstract
Background and Objectives: This paper presents a robust passivity-based voltage controller (PBVC) for robot manipulators with n degree of freedom in the presence of model uncertainties and external disturbance.Methods: The controller design procedure is divided into two steps. First, a model-based controller ...
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Background and Objectives: This paper presents a robust passivity-based voltage controller (PBVC) for robot manipulators with n degree of freedom in the presence of model uncertainties and external disturbance.Methods: The controller design procedure is divided into two steps. First, a model-based controller is designed based on the PBC scheme. An output feedback law is suggested to ensure the asymptotic stability of the closed-loop error dynamics. Second, a regressor-free adaptation law is obtained to estimate the variations of the model uncertainties and external disturbance. The proposed control law is provided in two different orders.Results: The suggested controller inherits both advantages of the passivitybased control (PBC) scheme and voltage control strategy (VCS). Since the proposed control approach only uses the electrical model of the actuators, the obtained control law is simple and also has an independent-joint structure. Moreover, the proposed PBVC overcomes the drawbacks of torque control strategy such as the complexity of manipulator dynamics, practical problems and ignoring the role of actuators. Moreover, computer simulations are carried out for both tracking and regulation purposes. In addition, the proposed controller is compared with a passivity-based torque controller where the simulation results show the appropriate efficiency of the proposed approach.Conclusion: The robust PBVC is proposed for EDRM in presence of external disturbance. To the best of our knowledge, it is the first time that a regressorfree adaptation law is obtained to approximate the lumped uncertainties according to the passivity-based VCS. Moreover, the electrical model of the actuators is utilized in a decentralized form to control each joint separately.
Original Research Paper
Electronics
Z. Kordrostami; S. Hamedi; F. Khalifeh
Abstract
Background and Objectives: High electron mobility transistors (HEMTs) are designed so that they are able to work at higher frequencies than conventional transistors and this has made them an attractive topic of research.Methods: Two developed designs of InGaAs/InAlAs high electron mobility transistors ...
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Background and Objectives: High electron mobility transistors (HEMTs) are designed so that they are able to work at higher frequencies than conventional transistors and this has made them an attractive topic of research.Methods: Two developed designs of InGaAs/InAlAs high electron mobility transistors have been studied. The proposed laterally contacted HEMTs satisfy the desired high frequency characteristics and are good candidates for high frequency applications. Two kinds of HEMTs have been designed and simulated: single-gate laterally contacted HEMT (SGLC-HEMT) and doublegate laterally contacted HEMT (DGLC-HEMT).Results: The proposed SGLC-HEMT exhibits 111 GHz current-gain cut-off frequency. By using double-gate design, the current-gain cut-off frequency has been increased to 256 GHz. The simulation results show that the maximum oscillation frequency for the proposed SGLC and DGLC HEMTs, are 410 GHz and 768 GHz, respectively. The maximum value of transconductance (gm) for SGLC-HEMT is obtained 620 mS/mm while it is 1130 mS/mm for DGLC-HEMT.Conclusion: In order to increase the fT and fmax, instead of decreasing the gate length which is a restricted solution because of short channel effects, a very efficient structure was proposed. The designed HEMT benefits from laterally source and drain contacts. The results showed superior performance of the laterally contacted HEMTs compared to top contacted ones. The best frequency response was obtained for DGLC-HEMT. The proposed DG-HEMT design could improve the current-gain cut-off frequency and maximum oscillation frequency to 256 GHz and 768 GHz, respectively. The comparison of the performance of the DGLC-HEMT with SGLC-HEMT and with previously reported double gate HEMTs, verified the significant improvements in DC and AC characteristics of the HEMTs caused by the proposed design.
Original Research Paper
Control
M. Siavash; V. Majd; M. Tahmasebi
Abstract
Background and Objectives: This article discusses a finite-time fault-tolerant consensus control for stochastic Euler-Lagrange multi-agent systems.Methods: First, the finite-time consensus controller of Euler-Lagrange multi-agent systems with stochastic disturbances is presented. Then, the proposed controller ...
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Background and Objectives: This article discusses a finite-time fault-tolerant consensus control for stochastic Euler-Lagrange multi-agent systems.Methods: First, the finite-time consensus controller of Euler-Lagrange multi-agent systems with stochastic disturbances is presented. Then, the proposed controller is extended as a fault-tolerant controller in the presence of faults in the actuators. In these two cases, the sliding-mode distributed consensus controllers are designed.Results: The results section is the most important part of the abstract and nothing should compromise its range and quality. This is because readers who peruse an abstract do so to learn about the findings of the study. The results section should therefore be the longest part of the abstract and should contain as much detail about the findings as the journal word count permits.Conclusion: The proposed theorems in this paper guarantee that the consensus tracking errors are bounded in probability and after a finite-time remain in a desired area close to the origin in the mean-square senses. The obtained theorems were applied to consensus control of the robotic manipulators to indicate the performance of the proposed controllers.
Original Research Paper
Electronics
A. Mouri Zadeh Khaki; E. Farshidi; K. Ansari Asl
Abstract
Background and Objectives: Beside acceptable performance, power consumption and chip area are important issues in embedded systems that should be taken into consideration.Methods: In this paper, a novel continuous-time 1-1 MASH ∆∑ Time-to-digital converter (TDC) is presented. Since the proposed ...
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Background and Objectives: Beside acceptable performance, power consumption and chip area are important issues in embedded systems that should be taken into consideration.Methods: In this paper, a novel continuous-time 1-1 MASH ∆∑ Time-to-digital converter (TDC) is presented. Since the proposed design utilizes 12-bit quantizer based on Gated Switched-Ring Oscillator (GSRO) for both stages, it has been implemented all-digitally. By using a novel structure, only one multi-bit counter is employed for both stages, therefore the required hardware for implementation of this work is much less than conventional TDCs. As a result, complexity, chip area and power consumption would decrease considerably.Results: We implemented the proposed design prototype on an Altera Stratix IV FPGA board. Measured results demonstrate that although this work uses less complex architecture in comparison with previous works, it provides appropriate performance such as 60.7 dB SNR within 8 MHz signal bandwidth at 400 MHz sampling rate while consuming 2.79 mW.Conclusion: Experimental results reveals suitability of the proposed TDC to be incorporated in fast and accurate applications such as ADPLLs and high-resolution photoacoustic tomography. Also, by adjusting the proposed novel structure with more stages higher order of noise-shaping can be attained to enhance SNR and time-resolution further.
Original Research Paper
Control
A. Mirzaei; A. Ramezani
Abstract
Background and Objectives: In this paper, a constrained cooperative distributed model predictive control (DMPC) is proposed. The proposed DMPC is based on linear adaptive generalized predictive control (AGPC) to control uncertain nonlinear large-scale systems.Methods: The proposed approach, has two main ...
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Background and Objectives: In this paper, a constrained cooperative distributed model predictive control (DMPC) is proposed. The proposed DMPC is based on linear adaptive generalized predictive control (AGPC) to control uncertain nonlinear large-scale systems.Methods: The proposed approach, has two main contributions. First, a novel cooperative optimization strategy is proposed to improve the centralized global cost function of each local controller. Second, using the proposed linear distributed AGPC (DAGPC), the mismatch between linearized and nonlinear models is compensated via online identification of the linearized model in each iteration of optimization.Results: The proposed novel cooperative optimization strategy decreases the computational burden of optimization process compared to conventional cooperative DMPC strategies. Moreover, the proposed linear DAGPC decreases the satisfaction time of the terminal condition compared to conventional DMPC methods. The paper establishes sufficient conditions for the closed-loop stability. The performance and effectiveness of proposed method is demonstrated through simulation of a quadruple-tank system for both certain and uncertain situations. The imposed uncertainty changes the system from minimum phase to nonminimum-phase situation. Closed-loop stability and proper convergences are concluded from simulation results of both situations.Conclusion: Most important advantages of proposed linear cooperative DAGPC are its less design complexity and consequently less convergence time compared to fully nonlinear DMPC methods, due to its online identification of the linearized model.
Original Research Paper
Communications
M. Sheikh-Hosseini
Abstract
Background and Objectives: Design of low-complexity receiver for space-time block coded (STBC) transmission over multiple-input multiple-output (MIMO) multiple-access channels has been subject of interest over the years. In this regard, zero-forcing receiver, as a low complexity receiver needing as many ...
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Background and Objectives: Design of low-complexity receiver for space-time block coded (STBC) transmission over multiple-input multiple-output (MIMO) multiple-access channels has been subject of interest over the years. In this regard, zero-forcing receiver, as a low complexity receiver needing as many receive antennas as the numbers of users, has received increasing attention.Methods: This paper investigates multiuser detection for STBC transmission over a flat-fading MIMO multiple-access channel consisting of co-channel users each with antennas and a zero-forcing coherent receiver equipping with receiving antennas. For the cases in which , it was previously claimed that it is impossible to extend this receiver to general scenarios of orthogonal STBC transmission with and .Results: We provide a theorem allowing this extension to any scenarios satisfying the theorem condition. Describing in more details, we first prove that zero-forcing receiver of antennas can successfully extend to any STBC transmission over MIMO multiple-access systems which provides an Alamouti-like structure for the inner product of equivalent channels between different receive antennas and users. Then, in order to gain more insight, the theorem role on extending zero-forcing receiver for transmission of orthogonal STBC over MIMO multiple-access systems with and , and also to other STBC schemes like generalized coordinate interleaved orthogonal design and Quasi-orthogonal STBC is investigated in more details. Finally, the average symbol error rate of considered scenarios are numerically evaluated and compered for different STBC schemes with various numbers of and .Conclusion: Generally speaking, it is concluded that extension of zero-forcing receiver to any scenarios of OSTBC transmissions over MIMO multiple-access channels exactly depends on satisfaction of the provided theorem and this receiver can be successfully employed in all scenarios providing an Alamouti-like structure for the inner product of equivalent channels between different receiving antennas and users.
Original Research Paper
Image Processing
A. Sharifi
Abstract
Background and Objectives: High resolution multi-spectral (HRMS) images are essential for most of the practical remote sensing applications. Pan-sharpening is an effective mechanism to produce HRMS image by integrating the significant structural details of panchromatic (PAN) image and rich spectral ...
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Background and Objectives: High resolution multi-spectral (HRMS) images are essential for most of the practical remote sensing applications. Pan-sharpening is an effective mechanism to produce HRMS image by integrating the significant structural details of panchromatic (PAN) image and rich spectral features of multi-spectral (MS) images.Methods: The traditional pan-sharpening methods incur disadvantages like spectral distortion, spatial artifacts and lack of details preservation in the fused image. The pan-sharpening approach proposed in this paper is based on integrating wavelet decomposition and convolutional sparse representation (CSR). The wavelet decomposition is performed on PAN and MS images to obtain low-frequency and high-frequency bands. The low-frequency bands are fused by exploring the CSR based activity level measurement.Results: The HRMS image is restored by implementing the inverse transform on fused bands. The fusion rules are constructed, thus to transfer the crucial details from source images to the fused image effectively.Conclusion: The proposed method produces HRMS images with rational spatial and spectral qualities. The visual outcomes and quantitative measures approve the eminence of the proposed fusion framework.
Original Research Paper
Control of Biological Systems
M. Mohammadian
Abstract
Background and Objectives: Regulation of protein expression in cellular level are so challenging. In cellular scale, biochemical processes are intrinsically noisy and many convenient controllers aren’t physically implementable.Methods: In this paper, we consider standard Lyapunov function and by ...
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Background and Objectives: Regulation of protein expression in cellular level are so challenging. In cellular scale, biochemical processes are intrinsically noisy and many convenient controllers aren’t physically implementable.Methods: In this paper, we consider standard Lyapunov function and by using Ito formula and stochastic analysis, we derive sufficient conditions for noise to state stability presented in the form of matrix inequalities. In the next step, by defining appropriate change of variables, matrix inequalities are transformed to Linear matrix inequalities which can be used to synthesize controller with the desired structure.Results: This paper deals with the design of implementable controller for stochastic gene regulatory networks with multiplicative and additive noises. In particular, we consider structural limitations that are present in real cellular systems and design the decentralized feedback that guarantees noise to state stability. Since the proposed conditions for controller design are in the form of linear matrix inequalities, controller gains can be derived efficiently through solving presented LMIs numerically. It is noteworthy that Because of its simple structure, the proposed controller can be implemented universally in many cells. Moreover, we consider a synthetic gene regulatory networks and investigate the effectiveness of the proposed controller by simulations.Conclusion: Our results provide a new method for designing Decentralized controller in gene regulatory networks with intrinsic and extrinsic noises. the proposed controller can be easily implemented in cellular environment.
Original Research Paper
Power
E. Limuchi; A. Taher; B. Ganji
Abstract
Background and Objectives: The microgrid voltage and frequency are strongly affected by active and reactive load fluctuations. Load change in microgrid may result in the lack of balance among generation and consumption and as a result change in output voltage and frequency. If load change is great enough, ...
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Background and Objectives: The microgrid voltage and frequency are strongly affected by active and reactive load fluctuations. Load change in microgrid may result in the lack of balance among generation and consumption and as a result change in output voltage and frequency. If load change is great enough, distribution generation cannot stabilize the microgrid. The main objective of this article is to control the distribution of active and reactive power related to an inverter-based distributed generation (DG) in the microgrid using intelligent methods. Methods: In this study, frequency and voltage of an active generator connected to the microgrid is also controlled with applying adaptive the fuzzy sliding mode control (AFSMC) and the droop control Methods To solve the problems related to design of the sliding mode controller, a compensator control system is suggested. A rule based on the Lyapunov stability theory is also introduced to ensure the stability of closed loop system.Results: Using MATLAB/SIMULINIK software, simulation results are provided for the proposed controller and its performance under different conditions for a typical power system is evaluated. Simulation of the considered power system is done to track different values of active and reactive power.Conclusion: The provided simulation results show the effectiveness of suggested method to regulate active and reactive power and to control voltage and frequency of the microgrid.
Original Research Paper
Communications
N. Danesh; M. Sheikhan; B. Mahboobi
Abstract
Background and Objectives: To achieve significant throughput, interference alignment (IA) is an encouraging technique for wireless interference networks. In this study, we design an aligned beamformer based on the interference leakage minimization (ILM) method to reduce the interference power for a ...
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Background and Objectives: To achieve significant throughput, interference alignment (IA) is an encouraging technique for wireless interference networks. In this study, we design an aligned beamformer based on the interference leakage minimization (ILM) method to reduce the interference power for a multiple-input multiple-output interference channel (MIMO-IC).Methods: To deal with the non-convexity of ILM problem, we used a non-convex programming method (i.e., difference of convex [DC]). In this way, the interference leakage function is reformulated to a DC function including difference of two convex terms. Then, an additive function is defined that includes the DC objective function and a penalty function.Results: We propose a novel DC-based IA algorithm that uses solutions of an upper bound of the additive function in each iteration; as the initial state for the next iteration. Through an iterative manner and for the large values of the penalty factor, the solutions of upper bound function converge to the solutions of the original DC objective function (i.e., interference leakage function).Conclusion: In contrast to the frequent IA methods, the proposed DC-based IA algorithm updates transmit- and receive-beamformers in each iteration jointly (not alternately). Simulation results indicate that the proposed method outperforms some competitive IA algorithms by providing more throughputs and less interference leakage.
Original Research Paper
Hardware
A. Oloomi; H. Khanmirza
Abstract
Background and Objectives: Nowadays, video hosting services receive and stream videos using standard protocols like Real-Time Messaging Protocol (RTMP). During the streaming process, video file streams are usually divided into small multi-second parts, and the player receives these parts instead of the ...
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Background and Objectives: Nowadays, video hosting services receive and stream videos using standard protocols like Real-Time Messaging Protocol (RTMP). During the streaming process, video file streams are usually divided into small multi-second parts, and the player receives these parts instead of the whole file at once. Most of the streaming protocols are capable of adaptive streaming and tolerating faults like device failures, and link disconnections. Faults might affect the performance of live streaming in terms of packet loss, latency, jitter, and video quality. The software-defined networking paradigm has also gained momentum in enterprise networks due to its lower-cost management and better network utilization. However, full migration from the current networks to the SDN model is not practical.Methods: The purpose of this study is to investigate the effectiveness of fault tolerance mechanisms of RTMP protocol on hybrid software-defined networks (SDN). In this paper, a practical and straightforward hybrid network architecture is proposed for gradual migration from traditional IP networks. Then, the performance of the RTMP protocol is compared for live video streaming on this network with different streams facing multiple failures.Results: Our experiments show that network failure recovery time in SDN is directly depends on the video stream recovery time while in traditional networks, streams need to be buffered again and it takes another several seconds due to the long interruption time. We propose an equation to give a rough estimation of data loss in SDN network during failures based on our observations which helps us in comparisons. We also demonstrate the average switching time in the SDN networks is almost half of the switching time in traditional networks.Conclusion: Our experiments proves, practically, video recovery time in SDN is less than a traditional network and has more correspondence with mechanisms of RTMP.
