Analysis of metothods determining the value of the flow’s speed when entering the lock chamber

The purpose of this work is to compare the results of calculating the velocities of the flow around the ship's hull when it enters the lock chamber using various methods. The article presents the mathematical dependences obtained by various authors in the course of their research depending on the coefficient of constraint of the lock chamber by the ship's hull. An attempt to determine the influence of the height of the wave that arises in front of the stem in the process of entry which creates a slope of the water surface and the effect of this factor on the speed of the flowing stream is made. It was found that the values ​​of the flow velocities calculated by various methods have discrepancies. And the methods themselves do not allow determining the speed of the flow around when large-tonnage vessels enter the lock chamber of an extremely small width. The authors proposed a simple technique for calculating the flow velocity for cases of large values ​​of the constraint coefficient using an auxiliary graph.

DEVELOPMENT OF A MULTIPATH ROUTING ALGORITHM IN SOFTWARE-DEFINED COMMUNICATION NETWORKS

The paper describes the development of routing algorithm in software-defined communication networks using the principle of multi-path message delivery. The use of the OpenFlow protocol as the main one for connecting data- and control-plane devices between each other, that is, programmable switches with the controller, allows us to take the network topology presented in undirected weighted graph form as the initial data for the algorithm. There are known solutions to the problem of finding ways to transmit data in a communication network, as a rule, using the network resource reservation protocol, but additional restrictions are imposed on the network, since RSVP has a low degree of scalability, respectively, inappropriate consumption of computing resources and storage system resources of individual routers. In view of the above, an algorithm has been developed for finding a set of paths on a graph with the construction of an auxiliary graph based on the original one. Conditions are given under which an auxiliary graph can be constructed from the initial one. The algorithm takes into account the possibility of constructing several paths passing through one vertex, while meeting the requirements for the delay of the input data stream. To expand the functionality and possible areas of application of the algorithm for finding a set of paths, a criterion for the required total throughput by a set of data transmission paths is introduced. Conditions for constructing paths from a vertex to set of vertices are given. The algorithm presented in the work has an order of magnitude less time complexity, which allows you to quickly respond to changes in the data transmission network, while the most significant differences in the time spent on building a set of paths are noticeable with an increase in nodes in the data transmission network and the number of possible paths.

The Graph Reasoning Approach Based on the Dynamic Knowledge Auxiliary for Complex Fact Verification

Complex fact verification (FV) requires fusing scattered sequences and performing multi-hop reasoning over these composed sequences. Recently, by employing some FV models, knowledge is obtained from context to support the reasoning process based on pretrained models (e.g., BERT, XLNET), and this model outperforms previous out-of-the-art FV models. In practice, however, the limited training data cannot provide enough background knowledge for FV tasks. Once the background knowledge changed, the pretrained models’ parameters cannot be updated. Additionally, noise against common sense cannot be accurately filtered out due to the lack of necessary knowledge, which may have a negative impact on the reasoning progress. Furthermore, existing models often wrongly label the given claims as ‘not enough information’ due to the lack of necessary conceptual relationship between pieces of evidence. In the present study, a Dynamic Knowledge Auxiliary Graph Reasoning (DKAR) approach is proposed for incorporating external background knowledge in the current FV model, which explicitly identifies and fills the knowledge gaps between provided sources and the given claims, to enhance the reasoning ability of graph neural networks. Experiments show that DKAR put forward in this study can be combined with specific and discriminative knowledge to guide the FV system to successfully overcome the knowledge-gap challenges and achieve improvement in FV tasks. Furthermore, DKAR is adopted to complete the FV task on the Fake NewsNet dataset, showing outstanding advantages in a small sample and heterogeneous web text source.

CYCLIC PERMUTATIONS IN THE METHODS OF COMBINATORIAL OPTIMIZATION ON THE BASIS OF CYCLIC TRANSFERS

Permutations sets are very often considered in theoretical and applied research in the field of combinatorics andcombinatorial optimization. By now many properties of permutations have been investigated, in particular those associatedwith the cyclic structure of permutations. To solve optimization problems on combinatorial sets, a number of methodshave been developed and successfully used. Among them, there are methods for finding exact, approximate, and heuristicsolutions. Among the search methods for an approximate solution, search methods in the neighborhood are widely used.Among the combinatorial search methods in the neighborhood, it is necessary to distinguish a group of methods that usescyclic transfers. A general search scheme using cyclic transfers is known. It is based on the search for a cyclic transferin the auxiliary graph. But the features of the tasks being solved sometimes do not allow constructing an auxiliary graphand using the existing search methods. In such cases, an alternative approach is proposed. This is a general strategy forsolving problems using cyclic transfers, which is a modification of the strategy of Thompson and Orlin. We propose theconstruction of cyclic transfers based not on the use of an auxiliary graph, but based on the set of cyclic permutationsand its properties to obtain cyclic transfers. To demonstrate the strategy for solving combinatorial optimization problemsdescribed in the article, one of the vehicle routing problems was solved. Computational experiments were conducted todemonstrate the effectiveness of the proposed strategy. Their results are given in the article.