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  • Author: Jurijs Lavendels x
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A comparison of subset selection and adaptive basis function construction for polynomial regression model building

A comparison of subset selection and adaptive basis function construction for polynomial regression model building

The approach of subset selection in polynomial regression model building assumes that the chosen fixed full set of predefined basis functions contains a subset that is sufficient to describe the target relation sufficiently well. However, in most cases the necessary set of basis functions is not known and needs to be guessed - a potentially non-trivial (and long) trial and error process. In our previous research we considered an approach for polynomial regression model building which is different from the subset selection - letting the regression model building method itself construct the basis functions necessary for creating a model of arbitrary complexity without restricting oneself to the basis functions of a predefined full model. The approach is titled Adaptive Basis Function Construction (ABFC). In the present paper we compare the two approaches for polynomial regression model building - subset selection and ABFC - both theoretically and empirically in terms of their underlying principles, computational complexity, and predictive performance. Additionally in empirical evaluations the ABFC is compared also to two other well-known regression modelling methods - Locally Weighted Polynomials and Multivariate Adaptive Regression Splines.

Open access
Modern Approaches to Building Recommender Systems for Online Stores

Abstract

The article presents current approaches to solving the problem of building recommender systems designed to intellectualize the user interface of online stores. Much attention is paid to modern methods of building recommender systems, analysing their strengths and weaknesses. Of greatest interest are the criteria for selecting effective methods for specific online stores and the authors’ concept of a typical recommender system of electronic commerce.

Open access
Evolution and Development Prospects of Information System Design Methodologies

Abstract

The article investigates different approaches to the design of information systems. Much attention is paid to comparative analysis of criteria for selecting methodologies for software development, and also to not well-known methodology of DevOps (Development & Operation) [1], [2], which aims at consolidation of software developers (Development) and IT professionals’ (Operation) efforts, and automation of implementation process. In conclusion, based on the retrospective analysis and practical experience, the authors formulate regularities and prospects of information systems design methodology development.

Open access
Experiment Plan as a Discreet System Equilibrium State

Abstract

The method of obtaining the plan of experiments in multidimensional space is considered in the paper. The method is based on assumptions of uniform distribution of charged particles in infinite space. To obtain the plan of experiments, the infinite multidimensional space is replaced with a hypercube whose surface models influence infinite space. The software is developed, and practical results in two-dimensional space are acquired. There are no basic problems to carry out calculations in multidimensional space.

Open access
Virtual Observation Environment for Training and Monitoring of Insurance Software End-Users

Abstract

Technological tools for the mastering of insurance software product remotely by end-users are described. To ensure distance training, two independent channels have been simultaneously used: one for video-audio conference providing trainer-trainee(s) communication and second one for collaboration between a trainer and trainee(s) showing software execution and control over trainee’s working with the software. The proposed solution has been approbated in several focus groups that give an evidence of its practical viability and applicability

Open access
Discrete Models in Research of Wave Processes in Rod Structures of Radio-Electronic Means

Abstract

The article shows the relevance of the application of discrete models of rod structures of radio-electronic means (REM) for the study of their behaviour under transient loading. A discrete model of the propagation of harmonic waves in the rod and the study of standing waves are proposed. Computational experiments using the proposed model are conducted. The results show that the model accurately reflects qualitative dynamics of the physical processes in the elastic rod while the waves of elastic deformations are passing through. The proposed models are used for software implementations of systems of mechanical simulation of the behaviour of rod structures.

Open access
Modernisation of Endoscopic Equipment Using 3D Indicators

Abstract

The development of new software to improve the operation of modernised and developed technological facilities in different sectors of the national economy requires a systematic approach. For example, the use of video recording systems obtained during operations with the use of endoscopic equipment allows monitoring the work of doctors. Minor change of the used software allows using additionally processed video fragments for creation of training complexes. The authors of the present article took part in the development of many educational software and hardware systems. The first such system was the “Contact” system, developed in the eighties of the last century at Riga Polytechnic Institute. Later on, car simulators, air plan simulators, walking excavator simulators and the optical software-hardware training system “Three-Dimensional Medical Atlas” were developed. Analysis of various simulators and training systems showed that the computers used in them could not by themselves be a learning system. When creating a learning system, many factors must be considered so that the student does not receive false skills. The goal of the study is to analyse the training systems created for the professional training of medical personnel working with endoscopic equipment, in particular, with equipment equipped with 3D indicators.

Open access
Determination of Vibrational Displacement Measurement Error Based on the Blurring Analysis of a Round Mark Image

Abstract

The relevance and nature of a new technology for measurement of vibrational displacement of a material point through normal toward the object plane are stated in the article. This technology provides registration and processing of images of a round mark or a matrix of round marks, which are applied to the surface of a control object. A measuring signal here is the module of radius increment of the round mark image at vibrational blurring of this image. The method for calculation of the given error of measurements, as a function of a number of pixels of the round mark image, has been developed and proven in the present research. The results of pilot studies are given. Linearity of transformation of the measured size into a measuring signal has been proven. The conditions of a technical compromise between the field of view area of a recording device during distribution measurement of vibrational displacements along the surface of a control object, and the accuracy of this measurement are determined. The results are illustrated with numerical examples of calculations of the given error of measurements in the set field of view and the one at the given maximum set error of measurements.

Open access