Simulation of Optimum Offer Prices in the Contract System in State and Municipal Procurement

The work is aimed at solving the actual problem of estimating the optimal offer price with participation in tenders on electronic platforms. The proposed approach is based on the use of the Monte Carlo method for simulation in order not only to adequately assess the cost of the proposed project, but also to predict the demand for the project under different conditions, as well as to simulate the behavior and intentions of the auction participants. The constructed model allows us to study the pricing mechanism on electronic trading platforms. With the help of the presented simulation methods, the estimation of the optimal price of the contract proposal depending on the number of competitors and the contract value, as well as the intentions of the competitors’ participation in the auction, the simulation results are presented

Graph Methods for Describing the Trade Profile of a Region

The work is devoted to the actual problem of building the trade profile of the region and studying the sustainability of regional foreign trade relations by analyzing the results of the region’s foreign economic activity. The aim of the work is to develop a method for describing the trade profile of the region based on graph theory, as well as to assess the possibility of interpreting the behavior of the identified groups of goods from the point of view of analyzing the dynamics of import and export volumes. As the main hypothesis, the paper uses the statement that the network model of describing the foreign trade relations of the region should be balanced with respect to the expectations of suppliers and consumers of products, otherwise there is an imbalance that generates changes in the structure of foreign trade relations. A methodology for the study of foreign economic relations and the development of a trade region based on them using network graphs and a cluster approach is proposed, which makes it possible to identify stable groups of goods and, on their basis, assess the main trends in changes and the potential for the development of foreign economic activity in the region. We consider the features of calculating the adjacency matrix for constructing a graph, as well as identifying groups of vertices connected to each other in order to identify complete subgraphs — clicks, which allows us to identify the main time-stable commodity groups on which the foreign economic activity of the region depends. The described methodology should be used to improve the efficiency of building and describing the trade profile of the region in order to manage the development of foreign economic activity in the region, study the properties of product groups and their characteristics

Magnetically operated nanorelay based on two single-walled carbon nanotubes filled with endofullerenes Fe@C20

Structural and energy characteristics of the smallest magnetic endofullerene Fe@C20 have been calculated using the density functional theory approach. The ground state of Fe@C20 is found to be a septet state, and the magnetic moment of Fe@C20 is estimated to be 8 Bohr magnetons. Characteristics of an (8,8) carbon nanotube with a single Fe@C20 inside are studied in the framework of the semiempirical approach. The scheme of a magnetic nanorelay based on cantilevered nanotubes filled with magnetic endofullerenes is elaborated. The proposed nanorelay is turned on as a result of bending of nanotubes by a magnetic force. Operational characteristics of such a nanorelay based on (8,8) and (21,21) nanotubes fully filled with Fe@C20 are estimated and compared to the ones of a nanorelay made of a (21,21) nanotube fully filled with experimentally observed (Ho3N)@C80 with the magnetic moment of 21 Bohr magnetons. Room temperature operation of (21,21) nanotube based nanorelays is shown.Comment: 18 pages, 9 figure

Hierarchical clustering methods in a task to find abnormal observations based on groups with broken symmetry

The work is aimed at solving the actual problem of identification and interpretation of anomalous observations in the study of socio-economic processes. The proposed method is based on the use of a cluster approach to detecting anomalous observations. Clustering is performed using hierarchical methods, which are a set of data ordering algorithms aimed at creating dendrograms consisting of groups of observed points. In the case of mixed data consisting of numeric and categorical variables, it is proposed to use the Gower distance as a metric for distances between elements. Clustering quality is evaluated based on the sum of squares of metric distances between objects within the cluster and the average width of the silhouette. These indicators allow you to select the optimal number of clusters and evaluate the quality of the split results. The dendrogram can be used to study the symmetry groups of cluster systems and the causes of symmetry breaking. Anomaly detection is performed by analyzing the results of hierarchical clustering and identifying branches of the dendrogram that are located at the initial levels of tree construction and do not have branches. The implemented method makes it possible to more accurately interpret the results of clustering with respect to determining errors of the first and second kind in the form of anomalous observations in the data set. Using the described method, it is possible to effectively investigate socio-economic systems and manage their development

Полиморфная нейроэпиталиальная опухоль низкой степени злокачественности молодого возраста (PLNTY), новые радиологические особенности: клинический случай

A new form of morphologically and molecularly distinguishable epileptogenic neoplasia with characteristic microscopic findings and a distinct DNA methylation signature as well as frequent genetic anomalies, was revealed in 2017; the tumor was called polymorphous low-grade neuroepithelial tumor of the young (PLNTY). Several specific radiological patterns found in PLNTY when compared with the results of a pathomorphological study being useful in differential diagnosis with other epileptogenic tumors were mentioned in certain papers. Our paper is devoted to some particulars of the radiological picture in two children with pharmacoresistant epilepsy who underwent epileptic surgery with histological verification of PLNTY.В 2017 г. обнаружена новая форма морфологически и молекулярно различимой эпилептогенной неоплазии, имеющая характерные микроскопические находки и отчетливую сигнатуру метилирования ДНК, наряду с частыми генетическими аномалиями, получившая название полиморфная нейроэпителиальная опухоль низкой степени злокачественности молодого возраста (PLNTY). В литературе упоминается о нескольких специфических радиологических паттернах, встречающихся у PLNTY, которые при сопоставлении с результатами патоморфологического исследования могут быть полезны при дифференциальной диагностике с другими эпилептогенными опухолями. Мы сообщаем о некоторых особенностях радиологической картины у двух детей с фармакорезистентной эпилепсией, прошедших процедуру эпилептической хирургии с гистологической верификацией PLNTY.

Nanotube-Based NEMS: Control vs. Thermodynamic Fluctuations

Multi-scale simulations of nanotube-based nanoelectromechanical systems (NEMS) controlled by a nonuniform electric field are performed by an example of a gigahertz oscillator. Using molecular dynamics simulations, we obtain the friction coefficients and characteristics of the thermal noise associated with the relative motion of the nanotube walls. These results are used in a phenomenological one-dimensional oscillator model. The analysis based both on this model and the Fokker-Planck equation for the oscillation energy distribution function shows how thermodynamic fluctuations restrict the possibility of controlling NEMS operation for systems of small sizes. The parameters of the force for which control of the oscillator operation is possible are determined.Comment: 40 pages, 12 figure

Environmental Improvement Of Opencast Mining

Existing classifications of waste dumps in the quarries are given and their phenomenological nature is clarified. The need to identify the essence of the term "dump" is shown as well as the idea of "dump" as an artificial formation with everted and mixed rocks distanced from the quarry. Essential classification of man-made rock formations in quarries is developed. Characteristic of variations of man-made waste formations in quarries is developed. To reduce harmful effects of open-pit mining, dumps should be substituted with strat-lays - man-made structures relevant to natural stratification of litho-substances. Construction of strat-lays would improve ecological and technological culture of open cast mining