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Integration of symmetry and macro-operators in planning
, Article 6th Mexican International Conference on Artificial Intelligence, MICAI 2007, Aguascalientes, 4 November 2007 through 10 November 2007 ; Volume 4827 LNAI , 2007 , Pages 1056-1066 ; 03029743 (ISSN); 9783540766308 (ISBN) ; Ghassem Sani, G ; Nakhost, H ; Sharif University of Technology
Springer Verlag
2007
Abstract
Macro-operators are sequences of actions that can guide a planner to achieve its goals faster by avoiding search for those sequences. However, using macro-operators will also increase the branching factor of choosing operators, and as a result making planning more complex and less efficient. On the other hand, the detection and exploitation of symmetric structures in planning problems can reduce the search space by directing the search process. In this paper, we present a new method for detecting symmetric objects through subgraph-isomorphism, and exploiting the extracted information in macrooperator selection. The method has been incorporated into HSP2, and tested on a collection of...
On pancyclicity properties of OTIS networks
, Article 3rd International Conference on High Performance Computing and Communications, HPCC 2007, Houston, TX, 26 September 2007 through 28 September 2007 ; Volume 4782 LNCS , 2007 , Pages 545-553 ; 03029743 (ISSN); 9783540754435 (ISBN) ; Sarbazi Azad, H ; Sharif University of Technology
Springer Verlag
2007
Abstract
The OTIS-Network (also referred to as two-level swapped network) is composed of n clones of an n-node original network constituting its clusters. It has received much attention due to its many favorable properties such as high degree of scalability, regularity, modularity, package-ability and high degree of algorithmic efficiency. In this paper, using the construction method, we show that the OTIS-Network is Pancyclic if its basic network is Hamiltonian- connected. The study of cycle embeddings with different sizes arises naturally in the implementation of a number of either computational or graph problems such as those used for finding storage schemes for logical data structures, layout of...
Sparse component analysis in presence of noise using an iterative EM-MAP algorithm
, Article 7th International Conference on Independent Component Analysis (ICA) and Source Separation, ICA 2007, London, 9 September 2007 through 12 September 2007 ; Volume 4666 LNCS , 2007 , Pages 438-445 ; 03029743 (ISSN); 9783540744931 (ISBN) ; Babaie Zadeh, M ; Mohimani, G. H ; Jutten, C ; Sharif University of Technology
Springer Verlag
2007
Abstract
In this paper, a new algorithm for source recovery in under-determined Sparse Component Analysis (SCA) or atomic decomposition on over-complete dictionaries is presented in the noisy case. The algorithm is essentially a method for obtaining sufficiently sparse solutions of under-determined systems of linear equations with additive Gaussian noise. The method is based on iterative Expectation-Maximization of a Maximum A Posteriori estimation of sources (EM-MAP) and a new steepest-descent method is introduced for the optimization in the Mstep. The solution obtained by the proposed algorithm is compared to the minimum ℓ1-norm solution achieved by Linear Programming (LP). It is experimentally...
Fast sparse representation based on smoothed ℓ0norm
, Article 7th International Conference on Independent Component Analysis (ICA) and Source Separation, ICA 2007, London, 9 September 2007 through 12 September 2007 ; Volume 4666 LNCS , 2007 , Pages 389-396 ; 03029743 (ISSN); 9783540744931 (ISBN) ; Babaie Zadeh, M ; Jutten, C ; Sharif University of Technology
Springer Verlag
2007
Abstract
In this paper, a new algorithm for Sparse Component Analysis (SCA) or atomic decomposition on over-complete dictionaries is presented. The algorithm is essentially a method for obtaining sufficiently sparse solutions of underdetermined systems of linear equations. The solution obtained by the proposed algorithm is compared with the minimum ℓ1-norm solution achieved by Linear Programming (LP). It is experimentally shown that the proposed algorithm is about two orders of magnitude faster than the state-of-the-art ℓ1-magic, while providing the same (or better) accuracy. © Springer-Verlag Berlin Heidelberg 2007
Estimating the mixing matrix in sparse component analysis based on converting a multiple dominant to a single dominant problem
, Article 7th International Conference on Independent Component Analysis (ICA) and Source Separation, ICA 2007, London, 9 September 2007 through 12 September 2007 ; Volume 4666 LNCS , 2007 , Pages 397-405 ; 03029743 (ISSN); 9783540744931 (ISBN) ; Babaie Zadeh, M ; Jutten, C ; Sharif University of Technology
Springer Verlag
2007
Abstract
We propose a new method for estimating the mixing matrix, A, in the linear model x(t) = As(t),t = 1,...,T, for the problem of underdetermined Sparse Component Analysis (SCA). Contrary to most previous algorithms, there can be more than one dominant source at each instant (we call it a "multiple dominant" problem). The main idea is to convert the multiple dominant problem to a series of single dominant problems, which may be solved by well-known methods. Each of these single dominant problems results in the determination of some columns of A. This results in a huge decrease in computations, which lets us to solve higher dimension problems that were not possible before. © Springer-Verlag...
H-BayesClust: A new hierarchical clustering based on Bayesian networks
, Article 3rd International Conference on Advanced Data Mining and Applications, ADMA 2007, Harbin, 6 August 2007 through 8 August 2007 ; Volume 4632 LNAI , 2007 , Pages 616-624 ; 03029743 (ISSN); 9783540738701 (ISBN) ; Abolhassani, H ; Sharif University of Technology
Springer Verlag
2007
Abstract
Clustering is one of the most important approaches for mining and extracting knowledge from the web. In this paper a method for clustering the web data is presented which using a Bayesian network, finds appropriate representatives for each of the clusters. Having those representatives, we can create more accurate clusters. Also the contents of the web pages are converted into vectors which firstly, the number of dimensions is reduced, and secondly the orthogonality problem is solved. Experimental results show about the high quality of the resultant clusters. © Springer-Verlag Berlin Heidelberg 2007
Resource placement in networks using chromatic sets of power graphs
, Article 2nd International Symposium on Computer Science in Russia, CSR 2007, Ekaterinburg, 3 September 2007 through 7 September 2007 ; Volume 4649 LNCS , 2007 , Pages 158-167 ; 03029743 (ISSN); 9783540745099 (ISBN) ; Sarbazi Azad, H ; Akl, S.G ; Sharif University of Technology
Springer Verlag
2007
Abstract
In this paper, using the chromatic properties of power graphs we propose a new approach for placing resources in symmetric networks. Our novel placement scheme guarantees a perfect placement when such a solution is feasible in the topology. © Springer-Verlag Berlin Heidelberg 2007
SMPCS: Sub-optimal model predictive control scheduler
, Article 6th International Conference on Next Generation Teletraffic and Wired/Wireless Advanced Networking, NEW2AN 2006, St. Petersburg, 29 May 2005 through 2 June 2005 ; Volume 4003 LNCS , 2006 , Pages 554-565 ; 03029743 (ISSN); 3540344292 (ISBN); 9783540344292 (ISBN) ; Taheri, H ; Haeri, M ; Sharif University of Technology
Springer Verlag
2006
Abstract
An approximated quadratic programming algorithm is proposed to determine a model predictive controller, which is applied to the scheduling problem. We name the algorithm Sub-optimal Model Predictive Control Scheduler (SMPCS). The SMPCS prepares a platform to guarantee end to end proportional delay in DiffServ architecture. This paper investigates the complication of SMPCS and its implementation problems in high speed routers. In order to efficiently implement the controller we admit sub-optimal results against reduction in the complexity of the optimizer. Simulation results show that the proposed approximation improves speed of the controller considerably. © Springer-Verlag Berlin Heidelberg...
A provably secure short transitive signature scheme from bilinear group Pairs
, Article 4th International Conference on Security in Communication Networks, SCN 2004, Amalfi, 8 September 2004 through 10 September 2004 ; Volume 3352 , 2005 , Pages 60-76 ; 03029743 (ISSN) ; Salmasizadeh, M ; Mohajeri, J ; Sharif University of Technology
Springer Verlag
2005
Abstract
We present a realization of the transitive signature scheme based on the algebraic properties of bilinear group pairs. The scheme is proven secure, i.e. transitively unforgeable under adaptive chosen message attack, assuming hardness of the computational co-Diffie-Hellman problem in bilinear group pairs and the security of the underlying standard signature scheme under known message attack. Our scheme mostly conforms to previously designed schemes of Micali-Rivest and Bellare-Neven in structure; yet there are two contributions: firstly, we take advantage of bilinear group pairs which were previously used by Boneh, Lynn, and Shacham to build short signature schemes. Secondly, we show that a...
Modeling and solving a capacitated stochastic location-allocation problem using sub-sources
, Article Soft Computing ; Volume 20, Issue 6 , 2016 , Pages 2261-2280 ; 14327643 (ISSN) ; Mahdavi Amiri, N ; Shiripour, S ; Sharif University of Technology
Springer Verlag
Abstract
We study a capacitated multi-facility location-allocation problem in which the customers have stochastic demands based on Bernoulli distribution function. We consider the capacitated sub-sources of facilities to satisfy demands of customers. In the discrete stochastic problem, the goal is to find optimal locations of facilities among candidate locations and optimal allocations of existing customers to operating facilities so that the total sum of fixed costs of operating facilities, allocation cost of the customers, expected values of servicing and outsourcing costs is minimized. The model is formulated as a mixed-integer nonlinear programming problem. Since finding an optimal solution may...
An improved fruit fly optimization algorithm to solve the homogeneous fuzzy series–parallel redundancy allocation problem under discount strategies
, Article Soft Computing ; Volume 20, Issue 6 , 2016 , Pages 2281-2307 ; 14327643 (ISSN) ; Alikar, N ; Akhavan Niaki, S. T ; Sharif University of Technology
Springer Verlag
Abstract
In this paper, a mathematical formulation is first derived for a homogenous fuzzy series–parallel redundancy allocation problem, where both the system and its subsystems can only take two states of complete perfect and complete failure. Identical redundant components are included in order to achieve desirable system reliability. The components of each subsystem characterized by their cost, weight, and reliability, are purchased from the market under all-unit discount and incremental quantity discount strategies. The goal is to find the optimum combination of the number of components for each subsystem that maximizes the system reliability under total fuzzy cost and weight constraints. An...
Energy-spectral efficient resource allocation and power control in heterogeneous networks with D2D communication
, Article Wireless Networks ; 2018 ; 10220038 (ISSN) ; Sobhi Givi, S ; Kalbkhani, H ; Shayesteh, M. G ; Sharif University of Technology
Springer New York LLC
2018
Abstract
Heterogeneous networks (HetNets) provide the demand for high data rates. In this study, we analyze the coexistence of femtocells and device-to-device (D2D) communication with macrocells. Interference management and decreasing energy consumption are two important issues in HetNets. To this end, we propose an efficient fractional frequency reuse (FFR)-based spectrum partitioning scheme to reduce the cross-tier interference. We also propose to use different optimization problems for resource allocation in different tiers. For this purpose, an energy efficient optimization problem is applied to D2D user equipment. Further, an optimization problem based on the spectral efficiency, i.e.,...
A competitive error in variables approach and algorithms for finding positive definite solutions of linear systems of matrix equations
, Article Springer Proceedings in Mathematics and Statistics, 2 January 2017 through 5 January 2017 ; Volume 235 , 2018 , Pages 45-66 ; 21941009 (ISSN); 9783319900254 (ISBN) ; Mahdavi Amiri, N ; Sharif University of Technology
Springer New York LLC
2018
Abstract
Here, we refine our recent proposed method for computing a positive definite solution to an overdetermined linear system of equations with multiple right-hand sides. This problem is important in several process control contexts including quadratic models for optimal control. The coefficient and the right-hand side matrices are, respectively, named data and target matrices. In several existing approaches, the data matrix is unrealistically assumed to be error free. We have recently presented an algorithm for solving such a problem considering error in measured data and target matrices. We defined a new error in variables (EIV) error function considering error for the variables, the necessary...
Smooth modeling of solidification based on the latent heat evolution approach
, Article International Journal of Advanced Manufacturing Technology ; Volume 88, Issue 9-12 , 2017 , Pages 3041-3052 ; 02683768 (ISSN) ; Sharif University of Technology
Springer London
2017
Abstract
The regularity problem of heat conduction equation corresponding to modeling of solidification based on the latent heat evolution approach is considered in the present study. It is shown that the corresponding PDE is actually semi-smooth, an issue that has not been taken into account explicitly in the related literature. A general smoothing (regularization) strategy is introduced to solve this problem. More specifically, the smoothed version of the effective heat capacity method is presented in this work. The presented approach is applied to model the quasi steady-state heat transfer problem in the continuous casting process. Numerical experiments demonstrate the success of the presented...
Service composition and optimal selection in cloud manufacturing: landscape analysis and optimization by a hybrid imperialist competitive and local search algorithm
, Article Neural Computing and Applications ; 2018 ; 09410643 (ISSN) ; Houshmand, M ; Sharif University of Technology
Springer London
2018
Abstract
Cloud manufacturing as an emerging service-oriented manufacturing paradigm integrates and manages geographically distributed manufacturing resources such that complex and highly customized manufacturing tasks can be performed cooperatively. The service composition and optimal selection (SCOS) problem, in which manufacturing cloud services are optimally selected for performing subtasks, is one of the key issues for implementing a cloud manufacturing system. In this paper, we propose a new mixed-integer programming model for solving the SCOS problem with sequential composition structure. Unlike the majority of previous research on the problem, in the proposed model, the transportation between...
Efficiently computing the smallest axis-parallel squares spanning all colors
, Article Scientia Iranica ; Volume 24, Issue 3 , 2017 , Pages 1325-1334 ; 10263098 (ISSN) ; Mohades, A ; Abam, M. A ; Kazemi, M. R ; Sedighin, S ; Sharif University of Technology
Sharif University of Technology
2017
Abstract
For a set of colored points, a region is called color-spanning if it contains at least one point of each color. In this paper, we first consider the problem of maintaining the smallest color-spanning interval for a set of n points with k colors on the real line, such that the insertion and deletion of an arbitrary point takes O(log2 n) the worst-case time. Then, we exploit the data structure to show that there is O(n log2 n) time algorithm to compute the smallest color-spanning square for a set of n points with k colors in the plane. This is a new way to improve O(nk log n) time algorithm presented by Abellanas et al. [1] when k = !(log n). We also consider the problem of computing the...
Stochastic optimization using continuous action-set learning automata
, Article Scientia Iranica ; Volume 12, Issue 1 , 2005 , Pages 14-25 ; 10263098 (ISSN) ; Meybodi, M. R ; Sharif University of Technology
Sharif University of Technology
2005
Abstract
In this paper, an adaptive random search method, based on continuous action-set learning automata, is studied for solving stochastic optimization problems in which only the noisecorrupted value of a function at any chosen point in the parameter space is available. First, a new continuous action-set learning automaton is introduced and its convergence properties are studied. Then, applications of this new continuous action-set learning automata to the minimization of a penalized Shubert function and pattern classification are presented. © Sharif University of Technology
Optimization of higher order pulse shapers used for reduction of noise in amplifier circuits
, Article Scientia Iranica ; Volume 12, Issue 1 , 2005 , Pages 75-82 ; 10263098 (ISSN) ; Sharif University of Technology
Sharif University of Technology
2005
Abstract
Active components in amplifiers generate noise. Thus, amplifiers too, produce noise at their output and, therefore, increase the input signal to noise ratio. This is an undesirable feature, more particularly when one is dealing with weak input signals already combined with noise. Thus, reducing amplifiers' noise becomes a necessity for some applications. To overcome this problem, one approach consists of improving electronic device technology. Another approach is the use of advanced techniques in designing low noise amplifiers by taking advantage of pulse shapers. Pulse shapers generally consist of calculated filters made of integrator(s) and differentiator(s) that limit properly the...
Optimal production and maintenance control under a time variant demand
, Article Scientia Iranica ; Volume 12, Issue 1 , 2005 , Pages 26-33 ; 10263098 (ISSN) ; Sharif University of Technology
Sharif University of Technology
2005
Abstract
In this paper, optimal production and maintenance planning of a flexible manufacturing system under a time variant demand is considered. There is a preventive maintenance plan to reduce the failure rate of the machine. It is assumed that the failure rate of the machine is a function of its age and its maintenance rate. It is, also, assumed that the demand of the manufacturing product is time dependent and its rate depends on the level of the advertisement on that product, The objective is to maximize the expected discounted total profit of the firm over an infinite time horizon. To solve this optimization problem, first, an optimal control is characterized by a set of Hamilton-Jacobi-Bellman...
A genetic algorithm for resource investment problems, enhanced by the revised Akpan method
, Article Scientia Iranica ; Volume 12, Issue 1 , 2005 , Pages 90-98 ; 10263098 (ISSN) ; Kianfar, F ; Sharif University of Technology
Sharif University of Technology
2005
Abstract
In this paper, a genetic algorithm for solving a class of project scheduling problems, called Resource Investment Problems, is presented. Tardiness of the project is permitted with a defined penalty. The decision variables are the level of resources and the start times of the activities. The objective is to minimize the sum of resources and delay penalty costs, subject to the activities' precedence relations and some other constraints. A revised form of the Akpan heuristic method for this problem is used to find better chromosomes. Elements of the algorithm, such as chromosome structure, unfitness function, crossover, mutation, immigration and local search operations, are explained. The...