The search functionality is under construction.

Author Search Result

[Author] Ghader KARIMIAN(3hit)

1-3hit
  • A Timed-Based Approach for Genetic Algorithm: Theory and Applications

    Amir MEHRAFSA  Alireza SOKHANDAN  Ghader KARIMIAN  

     
    PAPER-Biocybernetics, Neurocomputing

      Vol:
    E94-D No:6
      Page(s):
    1306-1320

    In this paper, a new algorithm called TGA is introduced which defines the concept of time more naturally for the first time. A parameter called TimeToLive is considered for each chromosome, which is a time duration in which it could participate in the process of the algorithm. This will lead to keeping the dynamism of algorithm in addition to maintaining its convergence sufficiently and stably. Thus, the TGA guarantees not to result in premature convergence or stagnation providing necessary convergence to achieve optimal answer. Moreover, the mutation operator is used more meaningfully in the TGA. Mutation probability has direct relation with parent similarity. This kind of mutation will decrease ineffective mating percent which does not make any improvement in offspring individuals and also it is more natural. Simulation results show that one run of the TGA is enough to reach the optimum answer and the TGA outperforms the standard genetic algorithm.

  • Using Sum of Squares Decomposition for Stability of Hybrid Systems

    Mohammad Ali BADAMCHIZADEH  Sohrab KHANMOHAMMADI  Ghasem ALIZADEH  Ali AGHAGOLZADEH  Ghader KARIMIAN  

     
    PAPER

      Vol:
    E90-A No:11
      Page(s):
    2478-2487

    This paper deals with stability analysis of hybrid systems. Such systems are characterized by a combination of continuous dynamics and logic based switching between discrete modes. Lyapunov theory is a well known methodology for the stability analysis of linear and nonlinear systems in control system literature. Construction of Lyapunov functions for hybrid systems is generally a difficult task, but once these functions are defined, stabilization of the system is straight-forward. The sum of squares (SOS) decomposition and semidefinite programming has also provided an efficient methodology for analysis of nonlinear systems. The computational method used in this paper relies on the SOS decomposition of multivariate polynomials. By using SOS, we construct a (some) Lyapunov function(s) for the hybrid system. The reduction techniques provide numerical solution of large-scale instances; otherwise they will be practically unsolvable. The introduced method can be used for hybrid systems with linear or nonlinear vector fields. Some examples are given to demonstrate the capabilities of the proposed approach.

  • A New Efficient Stereo Line Segment Matching Algorithm Based on More Effective Usage of the Photometric, Geometric and Structural Information

    Ghader KARIMIAN  Abolghasem A. RAIE  Karim FAEZ  

     
    PAPER-Stereo and Multiple View Analysis

      Vol:
    E89-D No:7
      Page(s):
    2012-2020

    In this paper, a new stereo line segment matching algorithm is presented. The main purpose of this algorithm is to increase efficiency, i.e. increasing the number of correctly matched lines while avoiding the increase of mismatches. In this regard, the reasons for the elimination of correct matches as well as the existence of the erroneous ones in some existing algorithms have been investigated. An attempt was also made to make efficient uses of the photometric, geometric and structural information through the introduction of new constraints, criteria, and procedures. Hence, in the candidate determination stage of the designed algorithm two new constraints, in addition to the reliable epipolar, maximum and minimum disparity and orientation similarity constraints were employed. In the process of disambiguation and final matches selection, being the main problem of the matching issue, regarding the employed constraints, criterion function and its optimization, it is a completely new development. The algorithm was applied to the images of several indoor scenes and its high efficiency illustrated by correct matching of 96% of the line segments with no mismatches.