Sharif Digital Repository

Some fundamental and unique characteristics of space are (1) global perspective, (2) above the atmosphere, (3) gravity-free environment, (4) abundant resources, and (5) exploration of space itself. If the mission doesn't rely on some fundamental and unique characteristics of space, it will likely cost more to do in space than in air or on Earth [1]. On the other hand, design of complex systems like satellites involves selecting design parameters (DPs) to satisfy the required constraints while meeting desired performance objectives. These parameters are often coupled, and their relationships not easily understood, and it makes the design an iterative process with high complexity [2]. But in... 

For processes that repeat the same task an iterative control method can be applied that learns from the previous runs and corrects the tracking error for the next run. Meanwhile, a set membership identification technique is be combined with the regulation part to identify the plant response using the informative input-output data of previous observations. This combination method has been experimentally tested on a radio frequency machine and the results are presented in the paper. © 2019 EUCA  

Linear resolvers are position sensors that are being used in a wide range of applications for linear motion systems. The electromagnetic design of a linear resolver, similar to any other electromagnetic device, demands an accurate, functional, and fast tool. While the finite element method (FEM) is considered the most accurate tool for electromagnetic analysis, it is not a good candidate for an optimization-based design which is an iterative process. In this article, first off, an analytical tool based on the subdomain model is briefly presented. This model is very accurate and much faster than FEM. However, it has high computational time for iterative design and optimization processes.... 

The objective of this paper is to introduce and demonstrate an algorithm for stress-constrained topology optimization. The algorithm relies on tracking a level-set defined via the topological derivative. The primary advantages of the proposed method are: (1) the stresses are well-defined at all points within the evolving topology, (2) the finite-element stiffness matrices are well-conditioned, making the analysis robust and efficient, (3) the level-set is tracked through a simple iterative process, and (4) the stress constraint is precisely satisfied at termination. The proposed algorithm is illustrated through numerical experiments in 2D and 3D  

Heat-bath algorithmic cooling provides algorithmic ways to improve the purity of quantum states. These techniques are complex iterative processes that change from each iteration to the next and this poses a significant challenge to implementing these algorithms. Here, we introduce a new technique that on a fundamental level, shows that it is possible to do algorithmic cooling and even reach the cooling limit without any knowledge of the state and using only a single fixed operation, and on a practical level, presents a more feasible and robust alternative for implementing heat-bath algorithmic cooling. We also show that our new technique converges to the asymptotic state of heat-bath... 

We consider a mechanism design problem for the joint flow control and multipath routing in informationally decentralized networks with strategic agents. Based on a surrogate optimization approach, we propose an incentive mechanism that strongly implements the social-welfare maximizing outcome in Nash equilibria. This mechanism possesses several other desirable properties, including individual rationality and budget balance at equilibrium. More importantly, in contrast to the existing literature on the network resource allocation mechanisms, the proposed mechanism is dynamically stable, meaning that the Nash equilibrium (NE) of the game induced by the mechanism can be learned by the agents in... 

We propose a perturbation method for time division multiplexed (TDM) pumping fiber Raman amplifier (FRA). The method is based on the solution of Raman partial differential equations (PDEs) by a closed integral form. Taking the signals and pumps power as the interim solution and updating their values in an iterative process, Raman gain and pump/signal evolution can be calculated in any order of accuracy. In the first order of perturbation, some analytical formulas for the FRA dynamic control are obtained. Analytical formulas are employed for gain ripple minimization and also the gain clamping problem under channel reconfiguration. © 2009 Elsevier Inc. All rights reserved  

The performance of Co-flow fluidic thrust vectoring is a function of secondary flow characteristics and the fluidic nozzle geometry. In terms of nozzle geometry, wall shape and the secondary slot aspect ratio are the main parameters that control the vector angle. The present study aims to find a high quality wall shape to achieve the best thrust vectoring performance, which is characterized by the maximum thrust deflection angle with respect to the injected secondary air. A 3D computational fluid dynamics (CFD) model is employed to investigate the flow characteristics in thrust vectoring system. This model is validated using experimental data collected from the deflection of exhaust gases of... 

Mean field independent component analysis (MF-ICA) along with other chemometric techniques was proposed for obtaining more information from multi-component gas chromatographic-mass spectrometric (GC-MS) signals of essential oils (mandarin and lemon as examples). Using these techniques, some fundamental problems during the GC-MS analysis of essential oils such as varying baseline, presence of different types of noise and co-elution have been solved. The parameters affecting MF-ICA algorithm were screened using a 25 factorial design. The optimum conditions for MF-ICA algorithm were followed by deconvolution of complex GC-MS peak clusters. The number of independent components (ICs) (chemical...