Sharif Digital Repository

The great share of interruptions in distribution networks motivates distribution decision makers to establish various reliability enhancement strategies. Amongst, deploying remote controlled switch (RCS) can make a crucial contribution to the reduction of interruption costs. Nevertheless, the stochastic nature of contingencies affects the RCS worth and imposes substantial financial risk to RCS deployment projects. This paper proposes a mathematical model to consider the risk in the optimal RCS deployment problem. The model determines the number and location of RCSs such that the expected profit is maximized while financial risk is minimized. The risk is modeled through conditional... 

This letter investigates the problem of sparse signal recovery in the presence of additive impulsive noise. The heavy-tailed impulsive noise is well modeled with stable distributions. Since there is no explicit formula for the probability density function of SαS distribution, alternative approximations are used, such as, generalized Gaussian distribution, which imposes ℓp-norm fidelity on the residual error. In this letter, we exploit a continuous mixed norm (CMN) for robust sparse recovery instead of ℓp-norm. We show that in blind conditions, i.e., in the case where the parameters of the noise distribution are unknown, incorporating CMN can lead to near-optimal recovery. We apply... 

In this paper, a restricted structure of PID controller is proposed for automobile gas turbine by considering a LQG cost function. So PID Controller coefficients are calculated by minimizing this cost function. One of the most important characteristics of this approach, its ability to design various structure PID controllers by solving optimization problem only for one time, moreover it can approximate main optimization problem by a repetitive Quadratic optimization Problem (QP). This approach is convex optimization and has an analytic solution; therefore its calculations are not complicated. In defined cost function, there are two weighting functions, control error and control action; they... 

In future wireless networks, network functions virtualization lays the foundations for establishing a new dynamic resource management framework to efficiently utilize network resources. In this paper, a network service can be viewed as a chain of virtual network functions (VNFs), called a service function chain (SFC), served via placement, admission control (AC), and embedding into network infrastructure, based on the resource management objectives and the state of network. To fully exploit such a potential and reach higher network performance, resource management stages should be jointly performed. To this end, two main challenges are: how to present a system model that formulates the... 

The great share of interruptions in distribution networks motivates distribution decision makers to establish various reliability enhancement strategies. Amongst these strategies, deploying remote controlled switch (RCS) can make a crucial contribution to the reduction of interruption costs. Nevertheless, the stochastic nature of contingencies affects RCS worth and imposes substantial financial risk to RCS deployment projects. This paper proposes a mathematical model to consider the risk in the optimal RCS deployment problem. The model determines the number and location of RCSs such that the expected profit is maximized while financial risk is minimized. The risk is modeled through... 

With the recent advancements in deep learning, high performance neural networks have been introduced. These neural networks also can be used to solve similar problems in a transfer learning approach. Recently, several state-of-The-Art Convolutional Neural Networks (CNNs) are proposed for computer vision tasks. On the other hand, in-The-wild No-Reference (Blind) Image Quality Assessment (NR-IQA) problem is known as a challenging human perceptual problem. In this paper, a transfer learning approach is used to solve the problem of in-The-wild NR-IQA. With a few training times, the proposed neural network exceeds all the previous methods which are not using deep neural networks. Further, the... 

Disability and motor disorders are some of the problems that people may face due to some factors such as accident, spinal cord injuries, brain damage, and the presence of a problem in neurological commands due to stroke. One of the proposed methods for solving the problems of these people is the use of exoskeletons to generate movement. The main goal of this paper is the control of Sharif Exoskeleton Robot and the reduction of interaction force between user and robot by using human intent detection. This goal is done by estimating the knee torque of one degree of freedom in a swing phase using Hill model based on the EMG data from the thigh muscles. Accordingly, the calibration algorithm is... 

In this paper, we consider a multiple-input single-output (MISO) non-orthogonal multiple access (NOMA) system in the presence of an external single-antenna eavesdropper. We study secure downlink transmission strategies. The challenge is that the multiple antenna configurations make the successive interference cancellation (SIC) condition, which is necessary for applying NOMA schemes, much complex. We formulate the transmission power minimization problem under the quality of service (QoS), SIC and secrecy constraints. In particular, the transmission power minimization problems are formulated under both perfect channel state information (CSI) and the bounded CSI error models. These problems... 

In this paper, the problem of content caching in 5G cellular networks relying on social-aware device-to-device communications (DTD) is investigated. Our focus is on how to efficiently select important users (IUs) and how to allocate content files to the storage of these selected IUs to form a distributed caching system. We aim at proposing a novel approach for minimizing the downloading latency and maximizing the social welfare simultaneously. In particular, we first model the problem of maximizing the social welfare as a many-to-one matching game based on the social property of mobile users. We study this game by exploiting users' social properties to generate the utility functions of the... 

Motion estimation is an important field of video processing. Conventional block motion estimation methods consider all pixels equally. In this paper a new edge sensitive algorithm is proposed in which distortion of ridgelet coefficients is calculated partially and compared over all candidates. Using an edge boosting distortion function, edge pixels will have more important role since they introduce larger ridgelet coefficients. Inherent ability of ridgelet in representing edges with various directions in multi scale, makes it a powerful tool for edge pursuit. Proposed partial ridgelet distortion search (PRDS) do not reject any candidate without assessment while performs relatively fast since... 

Genetic algorithm for optimization of beam forming in spiral array antenna is used. The goal is to achieve a -20 dB in null over the wide frequency band. Our simulation shows -20 dB over 75 MHz Null Band width, in VHF band. © 2006 IEEE  

Recently, moment dual approach of sums of squares relaxations developed for polynomial optimization problems was successfully extended to optimization problems with polynomial matrix inequality constraints. In this paper, we first derive an efficient polynomial formulization for matrix rank minimization problem which does not add any slack variable or additional equality or inequality constraint. Using the aforementioned theory, then we propose a hierarchy of convex LMI relaxations to provide a sequence of increasingly tight lower bounds on the global minimum rank of an arbitrary matrix under linear and polynomial matrix inequality constraints. Surprisingly enough, these lower bounds are... 

In this paper we introduce a mathematical modeling tool (called Classic General Model: CGM) for the general problem of hardware-software codesign so that different partitioning algorithms can be easily and quickly developed and compared in this same framework. CGM introduces a simple but efficient model which supports single/multiprocessor, primal and dual approaches, fine or coarse granularity. CGM determines solutions by stating Mapping, Implementation and Permutation arrays. For judging among solutions of a certain algorithm, an Objective Function is defined. After modeling the problem by CGM we have a classic problem: finding the best values for elements of three arrays to optimize the... 

In this paper a new two-level method for stochastic control of large-scale systems is presented. This two-level approach is based on Interaction Balance Principle (Goal coordination) for optimization problem and a two-level computational algorithm using extended Kalman filter for the estimation one. The two-level optimizer uses a new coordinator which works by the gradient of interaction errors that improves the convergence rate of the solution. The significance and the applicability of the theoretical developments of this paper are also shown by a numerical example. © 2006 IEEE  

Distinguishing reflected waveforms from two separated targets which are very close to each other is an important challenge in radar signal processing. Pulse compression is a technique used for accounting for this problem. There are several methods for compressing such as phase coding waveform and the goal of this paper is finding these optimal codes. In this paper, by combining several contents, a new optimum method based on Genetic Algorithm is suggested. This method has low computational operation and its speed is faster than the other ordinary algorithms. This method is belonged to local or partial search methods and has following advantages: 1. It uses branch-and-bound strategy; 2. It's... 

The sensor-source geometry has a significant effect on accuracy of source localization problems. In a sensor placement problem, one attempts to optimally place the sensors in the surveillance area so as to optimize a performance criterion. Sensor placement methods mainly solve the associated problems without taking any specific constraint on permissible location of sensors into account. In practical applications, however, possible location for deployment of the sensors are subject to such limitations as environmental, industrial, and communication constraints, which affects the optimal sensor-source geometry. In this article, we consider the problem of optimal sensor placement, based on time... 

The problem of designing optimum filter banks for different applications is a popular research subject. It has also been shown that principal component filter banks (PCFB) are the optimum filter bank for many application. Existing methods to design FIR PCFBs are based on designing energy compaction filters. In this work we concentrate on designing FIR PCFB with the same frequency response as the ideal one. The presented approach results in filter banks with a very good approximation of ideal PCFB, as verified by simulations. © 2005 IEEE  

In this paper, we use the generalized regression neural network (GRNN) for the inverse scattering from perfectly conducting cylindrical targets illuminated by the transverse magnetic to z polarization  

Sometimes, in our capacity as professionals, and under certain circumstances, we find ourselves faced with an ethical problem such as a conflict of interest in which codes of ethics or available ethical problem-solving methods cannot help us decide upon the moral course of action to take. Hence, either the codes or methods are flawed, or we are not using them appropriately. A method claimed to be helpful in such situations is The New York Times Test (NYTT). © 1982-2012 IEEE  

This communication addresses the focusing problem in the millimeter-wave imaging systems. We categorize the focusing problem into the frequency focusing for wideband systems and the range focusing for narrowband systems. In an out-of-focus wideband system, a shifted shadow of the object is present in the reconstruction, whereas for a range out of the focused system, the recovered images are blurred. To overcome these issues, first, we theoretically show that the defocusing variations for both categories are bounded. Then, we present a universal formulation for focusing problem, which covers both wideband and narrowband systems. As the true focused images are sharp at the boundaries of the...