Abstract In system identification, many structures and approaches have been proposed to deal with systems with non-linear behavior. When applicable, the prediction error method, analogously to the linear case, requires minimizing a cost function that is non-convex in general. The issue with non-convexity is more problematic for non-linear models, not only due to the increased complexity of the model, but also because methods to provide consistent initialization points may not be available for many model structures. In this paper, we consider a non-linear rational finite impulse response model. We observe how the prediction error method requires minimizing a non-convex cost function, and propose a three-step least-squares algorithm as an alternative procedure. This procedure is an extension of the Model Order Reduction Steiglitz-McBride method, which is asymptotically efficient in open loop for linear models. We perform a simulation study to illustrate the applicability and performance of the method, which suggests that it is asymptotically efficient.

: This paper analyzes the properties of Catalan numbers and their relation to the Lattice Path combinatorial problem in cryptography. Specifically, analyzes the application of the appropriate combinatorial problem based on Catalan-key in encryption and decryption of files and plaintext. Accordingly, we use Catalan numbers for generating keys and within the experimental part we have applied the NIST (National Institute of Standards and Technology) statistical battery of tests for assessing the quality of generated keys was applied. A total of 12 quality assurance tests for Catalan-key were applied. A Java application is presented which allows the encryption and decryption of plaintext based on the generated Catalan-key and combinatorial problem of movement in integer network or Lattice Path. Experimental study yields the comparison of results in text encryption speed for combinatorial encryption methods (such as: Ballot Problem, Stack permutations and Balanced Parentheses) in comparison with Lattice Path method (in Java programming language).

The paper describes some authentication techniques based on face recognition with emphasis on 2D and 3D facial recognition technologies. The paper presents analyzes that show that the success of a biometric system requires the measurement of its performances through several different types of parameters. Presented are the features and comparative analysis of the two120 | Zoran Lončarević , Muzafer Saračević, Muhedin Hadžić dimensional method of face recognition in relation to three-dimensional ones, based on numerous researches published in professional and scientific papers. The paper emphasize that it is necessary to analyze, in addition to the system performance, the errors that occur in biometric systems during the process of registration, verification and identification. An OpenCV library has been analyzed with it’s over 500 functions that cover several areas of Computer Vision and the area of automatic format recognition.