DOI: 10.7256/2454-0714.2020.1.32292

Abstract: The subject of research is the process of designing a conveyor belt. The authors consider parameterization in geometric modeling of parts and components of equipment and the creation of custom libraries in Compass 3D as a means of reducing the complexity and improving the quality of the design process. The preliminary design is the design stage of the development of design documentation and aims to determine the fundamental design solutions for a general idea of the device, operating principles and dimensions of the product. It is advisable to develop a preliminary design before the stage of developing a technical project and creating design documentation. Today, at all stages of work on the project, modern computer-aided design (CAD) systems are used, which not only accelerate the design process, but also make it possible to demonstrate to the customer the finished project at the stage of making technical decisions. This allows making timely changes in accordance with the requirements of the customer and to carry out high-quality preparation of the project for its implementation. The volume and time for further stages of work depend on the timing of the presentation of the preliminary design, therefore, the use of three-dimensional modeling parametrization in CAD is an effective way for designing engineering objects. Parameterization when working with 3D models allows you to get a set of typical product designs based on a once-created model by changing the set values of the variables, which significantly reduces the time spent on the project.

DOI: 10.7256/2454-0714.2020.1.31728

Abstract: The paper presents the results of evaluating the informative value of quantitative and binary signs to solve the problem of finding semantically close sentences (paraphrases). Three types of signs are considered in the article: those built on vector representations of words (according to the Word2Vec model), based on the extraction of numbers and structured information and reflecting the quantitative characteristics of the text. As indicators of information content, the percentage of paraphrases among examples with a characteristic, and the percentage of paraphrases with a attribute (for binary characteristics), as well as estimates using the accumulated frequency method (for quantitative indicators) are used. The assessment was conducted on the Russian paraphrase corps. The set of features considered in the work was tested as input for two machine learning models for defining semantically close sentences: reference vector machines (SVMs) and a recurrent neural network model. The first model accepts only the considered set of signs as input parameters, the second - the text in the form of sequences and the set of signs as an additional input. The quality of the models was 67.06% (F-measure) and 69.49% (accuracy) and 79.85% (F-measure) and 74.16% (accuracy), respectively. The result obtained in the work is comparable with the best results of the systems presented in 2017 at the competition for the definition of paraphrase for the Russian language (the second result for the F-measure, the third result for accuracy). The results proposed in the work can be used both in the implementation of search models for semantically close fragments of texts in natural language, and for the analysis of Russian-language paraphrases from the point of view of computer linguistics.

DOI: 10.7256/2454-0714.2020.1.32244

Abstract: The author gives the presentation of the content and structural components of an electronic textbook using Excel and the programming language Visual Basic for Applications using an example of a textbook fragment. The methods of presenting theoretical material, modeling with a visual demonstration, automatic verification of the results of assignments, automatic visual display of the results of mastering the topic using the built-in Excel functions are described in detail. The codes of programs for automatic presentation of individual tasks, automatic data modeling based on built-in Excel functions and building a scatter chart with smooth curves are given. The research methodology is based on testing the capabilities of MS Excel and the built-in programming language Visual Basic for Applications to solve the tasks. In contrast to the tools available today for creating electronic educational resources, such a textbook is easily modifiable, allows you to change the scripts of the educational process, in addition to test tasks, present students with sets of individual tasks, and adapt tasks to the level of students. In addition, it is an effective didactic tool for simultaneously mastering the Excel spreadsheet processor and discipline that requires modeling or performing complex calculations and routine operations.

DOI: 10.7256/2454-0714.2020.1.32235

Abstract: The object of research is the shaping of a family of displacement curves used in designing the path of a tool that processes pocket surfaces. The subject of the study is the working displacement curves in the case of multiply connected areas. Working displacement curves are lines from which non-working sections have been removed. Non-working areas include self-intersecting loops of displacement curves and sections formed when intersecting displacement curves of opposing fronts. The paper presents methods for analyzing and cutting off non-working sections for cases of self-intersection and intersection of displacement curves of opposing fronts. The spatial geometric model of the formation of displacement curves is based on the cyclographic method of displaying space. As a tool for detecting non-working areas for the case of opposing fronts, a method of a testing beam is proposed. In the case of self-intersections of the displacement curves, non-working sections are cut off by the parameter of these lines at the points of self-intersection. The novelty of the study lies in the fact that the obtained mathematical model of the formation of displacement curves for multiply connected regions with contours of complex handicap curves makes it possible to obtain parametric equations of working lines at the output of the computational algorithm in a more reliable and simple way. This greatly simplifies the solution to the problem of automated design of the trajectory of the cutting tool. A comparative assessment of the proposed method of shaping a family of displacement curves with cutting off non-working sections and known methods using the distance function is performed.

DOI: 10.7256/2454-0714.2020.1.32275

Abstract: The author of the work has proposed an algorithm for determining catacaustics in a “source-reflector” optical system on a plane. Katakaustika is called the envelope of reflected rays from a given curve and the study of catacaustics in the design of optical systems is one of the main tasks. The paper gives examples of solving this problem and presents the corresponding visualization. Particular attention is paid to problems where the source and reflector are curved, because these tasks in the scientific literature have not been previously considered. The presented algorithm is based on the cyclographic projection of the spatial curve of the line and its optical property. It is versatile and suitable for all tasks where the source of optical radiation is given in the form of a central (point), parallel or scattered beam of direct (light rays). The main advantage of the algorithm is that in the end it turns out analytical, i.e. exact solution to the problem of determining catacaustics. The results of the study can be used in applied fields of geometric optics, as well as in various computer-aided design systems specializing in modeling lighting of geometric objects.