Larysa Burtseva

Optoelectronic Method for Structural Health Monitoring

Important engineering constructions require geometrical monitoring to predict their structural health during their lifetime. Monitoring by geodetic devices, vibration-based techniques, wireless networks or with GPS technology is not always optimal; sometimes it is impossible as shown in this article. A method based on geodetic measurements automation applying local optical scanners for monitoring is proposed. Its originality and contribution is based on the novel method of precise measurement of plane spatial angles. It considers robust invariant AD-conversion angle-to-code for dynamic angle, signal energetic center search method, initial reference scale adjustment, and uncertainty decrease using mediant fractions formalism for result approximation. An algorithm of electromechanic parts interaction for spatial angle encoding with beforehand set accuracy is described. It is shown that by its nature it is appropriate for practically unlimited uncertainty reduction: it is only limited by reasonable ratio ‘‘uncertainty/operation velocity’’. The operation range, accuracy, scanner operation velocity, and its adaptation to objects are determined and described. The experimental results confirm that optical device of presented passive scanning aperture overcomes all recently known compared optical devices for 3D coordinates recognition in a part of offset uncertainty. It is shown that the presented optoelectronic scanning aperture is a universal tool for various practical solutions.

Frequency measurement method for Mechatronic and Telecommunication applications

A fast frequency measurement method based on the pulse coincidence of two regular independent pulse trains and rational approximations in the number theory is presented. A numeric condition derived from number theory to stop the measurement process is deduced. This measurement method has application in many practical tasks of Mechatronics and Telecommunications where is possible to convert a parameter to frequency, and is necessary to measure fast changes in the parameter. Results of numeric simulation of the frequency measurement process are presented.

Tracking the Evolution of the Internet of Things Concept Across Different Application Domains

Both the idea and technology for connecting sensors and actuators to a network to remotely monitor and control physical systems have been known for many years and developed accordingly. However, a little more than a decade ago the concept of the Internet of Things (IoT) was coined and used to integrate such approaches into a common framework. Technology has been constantly evolving and so has the concept of the Internet of Things, incorporating new terminology appropriate to technological advances and different application domains. This paper presents the changes that the IoT has undertaken since its conception and research on how technological advances have shaped it and fostered the arising of derived names suitable to specific domains. A two-step literature review through major publishers and indexing databases was conducted; first by searching for proposals on the Internet of Things concept and analyzing them to find similarities, differences, and technological features that allow us to create a timeline showing its development; in the second step the most mentioned names given to the IoT for specific domains, as well as closely related concepts were identified and briefly analyzed. The study confirms the claim that a consensus on the IoT definition has not yet been reached, as enabling technology keeps evolving and new application domains are being proposed. However, recent changes have been relatively moderated, and its variations on application domains are clearly differentiated, with data and data technologies playing an important role in the IoT landscape.

Method for phase shift measurement using farey fractions

The phase shift of coherent signals and the time intervals can be measured with the method of coincidences of electrical pulses. The results are automatically obtained and represented like simple fractions. These fractions are rational approximations of the unknown parameter, which generally is an irrational number. Such approximations can be represented with continued fractions or Farey fractions. Definitions and properties of Farey fractions are presented. An original method for phase shift measurement based on the pulses coincidence principle, whose result is a Farey fraction, is described. In order to increase the measurement accuracy, the continuous formation of rational means is performed, to represent the measurement result. These simplify the data processing and provide more accurate results than traditional methods.

The promotion of antibacterial effects of ti6al4v alloy modified with TiO 2 nanotubes using a superoxidized solution

The purpose of the present study was to synthetize 80 nm diameter TiO2 nanotubes (NTs) on Ti6Al4V alloy using a commercially superoxidized water (SOW) enriched with fluoride to reduce anodization time and promote the antibacterial efficacy against Staphylococcus aureus (S. aureus). The alloy discs were anodized for 5 min and as a result, NTs of approximately 80 nm diameters were obtained with similar morphology as reported in previous studies using longer anodization times (1-2 h). Filed emissionscanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDX) were used to characterize the materials surfaces. The NTs showed significantly decreased S. aureus viability after 1, 3, and 5 days of culture in comparison to nonanodized alloy. Likewise, SEM analysis also suggested lower bacterial adhesion on the NTs surface. No differences in bacterial morphology and topography were observed on both materials, as analyzed by SEM and atomic force microscopy (AFM). In conclusion, 80 nm diameter NTs were grown on Ti6Al4V alloy in 5 min by using a SOW solution enriched with fluoride, which resulted in a material with promoted antibacterial efficacy against S. aureus for up to 5 days of in vitro culture when compared to nonanodized alloy.

Scheduling Methods for Hybrid Flow Shops with Setup Times

Many real manufacturing systems process a large number of product variants in the same flow. These products may differ in some optional components; consequently, the processing time on a machine differs from one product to the next, and the need to prepare one or more machines before beginning or after the finishing of jobs is frequently presented. The preparation activities are: machine adjustment and feeders preparation to process a next job, dismantling after a previous job, machine calibrating, inspection of accessories or tools, cleaning of the machines and adjacent areas, etc. In the scheduling theory, the time required to shift from one job to another on a given machine is defined as additional production cost or setup time. The scheduling problems, which consider the setup times, have a high computational complexity. Pinedo (2008) presents a proof of the NP-hardness of the single machine case with setup consideration. They are more complex when the resource model has the parallel machine environment.

Tessellation Methods for Modeling the Material Structure

Tessellation methods are a relatively new approach for modeling the structure of a material. In this paper, such structures are interpreted as sphere packing models, where molecules and atoms represent spheres of equal or different size. Based on the review of the literature, it is shown that the tessellation approach is a powerful method for modeling and simulating such structures with desirable metric and topological properties. Two basic tessellation methods are considered more in detail: the Delaunay tessellation and the Voronoi diagram in Laguerre geometry, as well as some of their generalizations. The principal concepts of both tessellation methods are briefly explained for a better understanding of the application details. It is noted that packing models created by tessellation methods are not based on the use of the gravity camp effect, which is a difference to numerical and mathematic programming modeling approaches. Therefore, tessellation methods permit the development of structures without taking into account the gravitation, what is important for modeling the structure on the microscopic and nano levels, where the influence of the gravitation is studied insufficiently. A review of the related literature is given, focusing on the details of the tessellation method and the particle size distribution.

Monosized sphere packing approach in the nanoporous structure modeling

In many structural models atoms appear as hard monosized spheres. The properties of nanostructured porous matrix filled by adsorbed substance strongly depend on the density of atoms in nanochannels, those can be interpreted as cylinders. The problem of densest packing of monosized spheres in a cylindrical container is considered. It belongs to the optimization problems of Computational Geometry and is known to be NP-hard, i.e. its exact solution cannot be obtained in a polynomial time. Some approaches of the problem, which are applicable for modeling of nanoporous structures, are discussed. The classifications of packing models and known maximal densities are given. Three approaches represent different approximations in the modeling of packings. Those are: i) the numerical simulation, based on the geometrical properties, wall effects, and determination of stable position of spheres under gravity; ii) the Voronoi-Delaunay network, which models the channel structure in 3D space; and iii) the non-linear mathematical programming methods employed for densest packing search through cylinder height minimizing. These methods can be used for diverse nanoporous structure designs.

Lot Processing in Hybrid Flow Shop Scheduling Problem

The scheduling problem in manufacturing systems, where the product components are processed by means of lot units (pallets, containers, boxes) of many identical items, has been recently subject of intense research in modern industry. Most of the common examples in production per lots can be found in serial production like digital devices manufacturing, assembly lines, and information service facilities. The lot processing and the use of batch machines for parallel execution are typical for modern manufacturing systems.

Implementation of Bin Packing Model for Reed Switch Production Planning

This paper presents a form to resolve a real problem of efficient material election in reed switch manufacturing. The carrying out of the consumer demands depends on the stochastic results of the classification process where each lot of switches is distributed into bins according to an electric measure value. Various glass types are employed for the switch manufacturing. The effect caused by the glass type variation on the switch classification results was investigated. Based on real data statistic analysis, the problem is reduced to the lot number minimizing taking into consideration the glass type, and interpreted as a bin packing problem generalization. On difference to the classic bin packing problem, in the considered case, an item represents a set of pieces; a container is divided into a number of bins (sub‐containers); the bin capacity is variable; there are the assignment restrictions between bins and sets of pieces; the items are allowed to be fragmented into bins and containers. The problem has ...