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On the design of fir optimum orthonormal filter banks
, Article 2005 IEEE International Conference on Acoustics, Speech, and Signal Processing, ICASSP '05, Philadelphia, PA, 18 March 2005 through 23 March 2005 ; Volume IV , 2005 , Pages 545-548 ; 15206149 (ISSN); 0780388747 (ISBN); 9780780388741 (ISBN) ; Nayebi, K ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2005
Abstract
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
Algorithm for equilibrium transit assignment problem
, Article Transportation Research Record ; Issue 1923 , 2005 , Pages 227-235 ; 03611981 (ISSN) ; Aashtiani, H. Z ; Sharif University of Technology
National Research Council
2005
Abstract
Transit assignment is an important problem in the literature of transportation. Almost all competitive algorithms in this area are strategy based. For uncongested transit networks, the problem may be formulated into an optimization problem for which good solution algorithms exist. A variational inequality formulation of the problem with several solution methods is also presented in the literature for congested networks. This paper is devoted to solving a transit assignment problem based on complementarity formulation using path flows. The solution algorithm exploits the three concepts of decomposition, path generation, and linearization. The procedure has been applied on a large-scale...
On the different actuation's ways of the spherically actuated platform manipulator
, Article DETC2005: ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, Long Beach, CA, 24 September 2005 through 28 September 2005 ; Volume 7 B , 2005 , Pages 785-792 ; 0791847446 (ISBN); 9780791847442 (ISBN) ; Pendar, H ; Zohoor, H ; Sharif University of Technology
American Society of Mechanical Engineers
2005
Abstract
In this article kinematic analysis of a 3 Leg-Spherically Actuated (3SA) parallel manipulator will be addressed. Since each leg has a spherical actuator (three inputs for each leg) and manipulator has three legs; totally, there are nine inputs. Due to the fact that the manipulator has six degree of freedom, only six independent inputs are needed. Thus actuation could be done in different ways. If the triangles representing base and platform are equilateral, there are twenty different ways of actuation that should be studied during forward kinematic analysis. Rather than adopting the standard Denavit-Hartenberg approach, a simple method for forward kinematic analysis for all these different...
Traffic information use modeling in the context of a developing country
, Article Periodica Polytechnica Transportation Engineering ; Volume 33, Issue 1-2 , 2005 , Pages 125-137 ; 03037800 (ISSN) ; Kermanshah, M ; Sharif University of Technology
Technical University of Budapest
2005
Abstract
The use of traffic information in the form of radio reports, as a solution to the problem of congestion, is one of the issues, which are of particular importance for large cities like Tehran. In this study, factors affecting the use of traffic information in the context of a developing country are examined for commuters in the city of Tehran using ordered logit models. Results based on the particular survey designed for this purpose are compared to those of a developed country. Regarding the use of information in the form of listening to the radio traffic reports, the models show that older commuters, commuters who adjust their departure time according to traffic conditions (those who are...
Generation expansion planning of stand-alone micro-power systems using MADM techniques
, Article 42nd International Universities Power Engineering Conference, UPEC 2007, Brighton, 4 September 2007 through 6 September 2007 ; 2007 , Pages 68-72 ; 1905593368 (ISBN); 9781905593361 (ISBN) ; Afsharnia, S ; Ehsan, M ; Kamalinia, S ; Sedighizadeh, M ; Sharif University of Technology
2007
Abstract
In this paper, Analytic Hierarchy Process and Data Envelopment Analysis are introduced as multi attribute decision making techniques in planning of standalone micro-power systems. The objective of the planning framework is to select the best configuration and capacity of different generating technologies in micro-power systems to minimize certain economical and environmental attributes. The economical attributes are capital cost and net present cost and the environmental attribute is emission. The proposed framework is illustrated by a case study on a real network in northern region of Iran
Identification of external power system linear dynamic equivalents as MIMO feedback blocks for the study system
, Article International Journal of Emerging Electric Power Systems ; Volume 8, Issue 5 , 21 Nov. 2007 , 2007 ; 1553779X (ISSN) ; Ranjbar, A. M ; Lesani, H ; Radmanesh, H ; Sharif University of Technology
2007
Abstract
The necessity of dynamic equivalents for power system analysis has been well known since the expansion of large interconnected power networks, and has been discussed during the last decades. The present paper proposes a new method for constructing dynamic equivalents of power systems. In this method, at the first step the "study system" is modeled completely via a single machineinfinite bus modeling procedure. Then the "external system" is identified as a MIMO feedback block of this model in such a manner that can include dynamic effects of the latter on the behavior of the former. The method is successfully experimented on a part of the Iranian southern network. Copyright © 2007 The...
A modified pressure-based algorithm to solve flow fields with shock and expansion waves
, Article Numerical Heat Transfer, Part B: Fundamentals ; Volume 46, Issue 5 , 2004 , Pages 497-504 ; 10407790 (ISSN) ; Mokarizadeh, V ; Sharif University of Technology
2004
Abstract
The use of collocated grid schemes in control-volume-based methods has resulted in developing different strategies for coupling mass and momentum governing equations. Defining two different velocity components at cell faces is one remedy to suppress the possible checkerboard problem in the solution domain. These velocity components are widely known as convected and convecting velocities which are normally used in the momentum and mass governing equations, respectively. However, the linearization of the nonlinear governing equations generates a number of lagged velocity components which must be carefully treated in a manner to preserve the conceptual definition of the convected and convecting...
Ising model on the edge-dual of random networks
, Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 69, Issue 6 2 , 2004 , Pages 066114-1-066114-10 ; 15393755 (ISSN) ; Sharif University of Technology
2004
Abstract
The Ising model with nearest-neighbor interactions on the edge dual of uncorrelated random networks was discussed. It was found that in the thermodynamic limit, the networks have a finite clustering. Low- and high-temperature expansions of Ising model on the edge dual of random networks were derived. A comparison of the critical behavior of Ising model on scale free random networks and their edge dual was performed. A simple relation was given between the partition function of an Ising model with nearest- and next-nearest-neighbor interactions on a tree like network and its edge dual
Iterative detection for V-BLAST MIMO communication systems based on expectation maximisation algorithm
, Article Electronics Letters ; Volume 40, Issue 11 , 2004 , Pages 684-685 ; 00135194 (ISSN) ; Nasiri Kenari, M ; Sharif University of Technology
2004
Abstract
By applying the expectation maximisation algorithm to the maximum likelihood detection of layered space-time codes, the conditional log-likelihood of a single layer is iteratively maximised, rather than maximising the intractable likelihood function of all layers. Computer simulations demonstrate the efficiency of the proposed detection scheme
Ising model on the edge-dual of random networks
, Article Physical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics ; Volume 69, Issue 6 , 2004 , Pages 10- ; 1063651X (ISSN) ; Sharif University of Technology
2004
Abstract
We consider the Ising model on the edge dual of uncorrelated random networks with arbitrary degree distribution. These networks have a finite clustering in the thermodynamic limit. High- and low-temperature expansions of Ising model on the edge dual of random networks are derived. A detailed comparison of the critical behavior of Ising model on scale free random networks and their edge dual is presented. © 2004 The American Physical Society
A generalized regression neural network to inverse scattering from cylindrical conducting targets
, Article IEEE Antennas and Propagation Society Symposium 2004 Digest held in Conjunction with: USNC/URSI National Radio Science Meeting, Monterey, CA, 20 June 2004 through 25 June 2004 ; Volume 1 , 2004 , Pages 213-216 ; 15223965 (ISSN) ; Barkeshli, K ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2004
Abstract
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
Parallelization of the Lattice Boltzmann model in simulating buoyancy-driven convection heat transfer
, Article 2004 ASME International Mechanical Engineering Congress and Exposition, IMECE, Anaheim, CA, 13 November 2004 through 19 November 2004 ; Volume 375, Issue 1 , 2004 , Pages 305-312 ; 02725673 (ISSN) ; Darbandi, M ; Schneider, G. E ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
2004
Abstract
The main objective of the current work is to utilize Lattice Boltzmann Method (LBM) for simulating buoyancy-driven flow considering the hybrid thermal lattice Boltzmann equation (HTLBE). After deriving the required formulations, they are validated against a wide range of Rayleigh numbers in buoyancy-driven square cavity problem. The performance of the method is investigated on parallel machines using Message Passing Interface (MPI) library and implementing domain decomposition technique to solve problems with large order of computations. The achieved results show that the code is highly efficient to solve large scale problems with excellent speedup. Copyright © 2004 by ASME
Parallel computation of a mixed convection problem using fully-coupled and segregated algorithms
, Article 2004 ASME International Mechanical Engineering Congress and Exposition, IMECE, Anaheim, CA, 13 November 2004 through 19 November 2004 ; Volume 375, Issue 1 , 2004 , Pages 313-322 ; 02725673 (ISSN) ; Banaeizadeh, A ; Schneider, G. E ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
2004
Abstract
In this work, parallel solution of the Navier-Stokes equations for a mixed convection heat problem is achieved using a finite-element-based finite-volume method in fully coupled and semi coupled algorithms. A major drawback with the implicit methods is the need for solving the huge set of linear algebraic equations in large scale problems. The current parallel computation is developed on distributed memory machines. The matrix decomposition and solution are carried out using PETSc library. In the fully coupled algorithm, there is a 36-diagonal global matrix for the two-dimensional governing equations. In order to reduce the computational time, the matrix is suitably broken in several...
Optimal planning of equipment maintenance and replacement on a variable horizon
, Article Scientia Iranica ; Volume 11, Issue 3 , 2004 , Pages 185-192 ; 10263098 (ISSN) ; Sharif University of Technology
Sharif University of Technology
2004
Abstract
In maintenance and replacement planning of an industry, the purchasing of new equipment on the market with some kind of technological improvement over existing equipment should be taken into account. Because of operating cost, ordinary and preventive maintenance expenses may be lower, production rate may be higher and the quality of output may be better, etc. The industry to be considered in this paper is the mining industry and the replaced equipment is the mine shovel. It is assumed that, at most, one new shovel can be purchased before the mine is exhausted. It is possible that the mine is given up before exhausted, because of the disadvantage of the expense and loss of the salvage value...
Periodic solution of a certain non-linear third order differential equation
, Article Scientia Iranica ; Volume 11, Issue 3 , 2004 , Pages 181-184 ; 10263098 (ISSN) ; Shadman, D ; Sharif University of Technology
Sharif University of Technology
2004
Abstract
In this paper, the third order differential equation x‴ + ψ (x′)x″ + (κ2 +ø (x))x′ + f(t, x = e(t) is considered. Under certain conditions on the functions appearing in the differential equation, the existence of periodic solutions is proved. Similar problems have been treated by authors in [4,6,7]. However, the method employed here is used by Reissig [1] and the results obtained are, in fact, a generalization of those in [1-3]. The conditions imposed on the nonlinear terms do not require the ultimate boundedness of all solutions. © Sharif University of Technology
A novel minimum time trajectory planning in terrain following flights
, Article 2003 IEEE Aerospace Conference, Big Sky, MT, 8 March 2003 through 15 March 2003 ; Volume 8 , 2003 , Pages 3755-3762 ; 1095323X (ISSN); 078037651X (ISBN); 9780780376519 (ISBN) ; Kosari, A. R ; Sharif University of Technology
2003
Abstract
A new methodology has been proposed to enhance inverse dynamics applications in the process of trajectory planning and optimization in Terrain Following Flights (TFF). The new approach uses least square scheme to solve a general two-dimensional (2D) Terrain Following Flight in a vertical plane. In the mathematical process, Chebyshev polynomials are used to model the geographical data of the terrain in a given route in a manner suitable for the aircraft at hand. The aircraft then follows the modeled terrain with sufficient clearance. In this approach the TF problem is effectively converted to an optimal tracking problem. Results show that. this method provides a flexible approach to solve the...
Optimal fuel core loading pattern design in PWR nuclear power reactors using genetic algorithms and fuzzy nonlinear programming
, Article Journal of Intelligent and Fuzzy Systems ; Volume 14, Issue 2 , 2003 , Pages 85-93 ; 10641246 (ISSN) ; Ghofrani, M. B ; Lucas, C ; Sharif University of Technology
2003
Abstract
In pressurized water reactors, the fuel reloading problem has significant meaning in terms of both safety and economics. An optimal loading pattern is defined as a pattern in which the local power peaking factor (Pq) is lower than a predetermined value during one cycle and the effective multiplication factor (keff) is maximized to extract the maximum energy. This article presents a specialized genetic algorithm for loading pattern design. The tests on well-researched cases have shown that the genetic algorithm is capable of finding better loading patterns than solutions found by direct search methods. However, most of the previous researchers have considered simple fitness (cost) functions;...
Multirate structures for arbitrary rate error control coding
, Article 2003 IEEE International Conference on Accoustics, Speech, and Signal Processing, Hong Kong, 6 April 2003 through 10 April 2003 ; Volume 4 , 2003 , Pages 245-248 ; 15206149 (ISSN) ; Nayebi, K ; Kasaei, S ; Sharif University of Technology
2003
Abstract
In this paper, we present the most general form for error control coding using finite field multi-rate filters. This method shows how different types of codes can easily be generated by multi-rate filters and filter banks. In all previous works, codes and syndromes were generated using prefilters. Here we present simple multi-rate structures for encoding and generating syndrome. We show that all kinds of arbitrary rate K/L, circulant linear codes can be generated by these structures. Then we claim that a similar simple structure for syndrome generation in all presented cases exist
Analysis of a dissimilar finite wedge under antiplane deformation
, Article Mechanics Research Communications, Exeter ; Volume 27, Issue 1 , 2000 , Pages 109-116 ; 00936413 (ISSN) ; Fariborz, S. J ; Sharif University of Technology
Elsevier Science Ltd
2000
Abstract
The dissimilar wedge with finite radius under antiplane shear deformation is analyzed. The finite Mellin transform is used to solve the governing differential equation. By simply letting the wedge radius approaches infinity, the solution is obtained
The new york times test: An intersubjective reconsideration
, Article IEEE Technology and Society Magazine ; Volume 41, Issue 1 , 2022 , Pages 18-22 ; 02780097 (ISSN) ; Taqavi, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
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