Context-Free Path Querying by Matrix Multiplication

Graph data models are widely used in many areas, for example, bioinformatics, graph databases. In these areas, it is often required to process queries for large graphs. Some of the most common graph queries are navigational queries. The result of query evaluation is a set of implicit relations between nodes of the graph, i.e. paths in the graph. A natural way to specify these relations is by specifying paths using formal grammars over the alphabet of edge labels. An answer to a context-free path query in this approach is usually a set of triples (A, m, n) such that there is a path from the node m to the node n, whose labeling is derived from a non-terminal A of the given context-free grammar. This type of queries is evaluated using the relational query semantics. Another example of path query semantics is the single-path query semantics which requires presenting a single path from the node m to the node n, whose labeling is derived from a non-terminal A for all triples (A, m, n) evaluated using the relational query semantics. There is a number of algorithms for query evaluation which use these semantics but all of them perform poorly on large graphs. One of the most common technique for efficient big data processing is the use of a graphics processing unit (GPU) to perform computations, but these algorithms do not allow to use this technique efficiently. In this paper, we show how the context-free path query evaluation using these query semantics can be reduced to the calculation of the matrix transitive closure. Also, we propose an algorithm for context-free path query evaluation which uses relational query semantics and is based on matrix operations that make it possible to speed up computations by using a GPU.Comment: 9 pages, 11 figures, 2 table

Current State of the Insurance Market in Uzbekistan

One of the most important achievements of Uzbekistan's development has been the formation of an insurance market environment and the elimination of the state monopoly on insurance. From the subsidiary sector of the economy, as insurance was in the years of Soviet power, insurance in Uzbekistan has been promoted to strategic positions over the past period. This is primarily due to the active state policy, in which the insurance market is considered by the state authorities as one of the main components of the market infrastructure of the country. Over 2016-2022, gross accrued insurance premium increased more than 4 times and amounted to more than 1.4 trillion soums, and the insurance penetration rate for these years was in the range from 0.34 to 0.7%. During the above period, the insurance density varied from 6.7 to 15.3 USD. The loss ratio at the end of 2022 was over 23%. At the end of 2022, 41 insurance companies were operating in the insurance market of Uzbekistan, of which 8 - in the life insurance industry. Not all domestic insurance companies are active players in the insurance market, 7 insurers have a market share of less than 1% in terms of insurance premiums. The insurance market of Uzbekistan is characterized by a very high geographical concentration. This is explained by the fact that although insurable objects are distributed throughout the territory of the republic, almost all financial flows are concentrated in the capital. The main share of insurance premium (more than 68%) is still formed in the city of Tashkent, which indicates the predominance of corporate insurance in the insurance portfolio of domestic insurers. The current stage of development of the domestic insurance market is characterized by insignificant sizes of authorized capitals of insurers both in the general insurance industry and in the life insurance industry. The size of total authorized capital of insurance companies in Uzbekistan as of January 1, 2023 amounted to about 1.8 trillion in soum terms. The state of the insurance market of Uzbekistan today is characterized by the following positive trends: -high growth rates of total insurance premium volume (not less than 10% annually) -presence in the market of 40 insurance companies in the general insurance industry, including three of them - with state-participation, which have been operating in the domestic insurance market for more than 20 years and are actually national brands - joint stock companies "Uzagrosugurta", "Kafolat" and export-import insurance company "Uzbekinvest", as well as 8 companies in the life insurance industry; sufficiently high degree of insurers' presence through branches, representative offices and a network of insurance agents in all regions of the country; availability of a large number of insurance agents (more than 7 thousand)

Jumping Evaluation of Nested Regular Path Queries

International audienceNested regular path queries are used for querying graph databases and RDF triple stores. We pro- pose a new algorithm for evaluating nested regular path queries on a graph from a set of start nodes in combined linear time. We show that this complexity upper bound can be reduced by making it de- pendent on the size of the query’s top-down needed subgraph, a notion that we introduce. For many queries in practice, the top-down needed subgraph is way smaller than the whole graph. Our algo- rithm is based on a novel compilation schema from nested regular path queries to monadic datalog queries. Its complexity upper bound follows from known properties of top-down datalog evaluation. As an application, we show that our algorithm permits to reformulate in simple terms a variant of a very efficient automata-based algorithm proposed by Maneth and Nguyen that evaluates navigational path queries in datatrees based on indexes and jumping. Moreover, it overcomes some limitations of Maneth and Nguyen’s: it is not bound to trees and applies to graphs; it is not limited to forward navigational XPath but can treat any nested regular path query and it can be implemented efficiently without any dedicated techniques, by using any efficient top-down datalog evaluator. We confirm the efficiency of our algorithm experimentally based on an implementation with LogicBlox

Multiple context-free path querying by matrix multiplication

Many graph analysis problems can be formulated as formal language-constrained path querying problems where the formal languages are used as constraints for navigational path queries. Recently, the context-free language (CFL) reachability formulation has become very popular and can be used in many areas, for example, querying graph databases, Resource Description Framework (RDF) analysis. However, the generative capacity of context-free grammars (CFGs) is too weak to generate some complex queries, for example, from natural languages, and the various extensions of CFGs have been proposed. Multiple context-free grammar (MCFG) is one of such extensions of CFGs. Despite the fact that, to the best of our knowledge, there is no algorithm for MCFL-reachability, this problem is known to be decidable. This paper is devoted to developing the first such algorithm for the MCFL-reachability problem. The essence of the proposed algorithm is to use a set of Boolean matrices and operations on them to find paths in a graph that satisfy the given constraints. The main operation here is Boolean matrix multiplication. As a result, the algorithm returns a set of matrices containing all information needed to solve the MCFL-reachability problem. The presented algorithm is implemented in Python using GraphBLAS API. An analysis of real RDF data and synthetic graphs for some MCFLs is performed. The study showed that using a sparse format for matrix storage and parallel computing for graphs with tens of thousands of edges the analysis time can be 10–20 minutes. The result of the analysis provides tens of millions of reachable vertex pairs. The proposed algorithm can be applied in problems of static code analysis, bioinformatics, network analysis, as well as in graph databases when a path query cannot be expressed using context-free grammars. The provided algorithm is linear algebra-based, hence, it allows one to use high-performance libraries and utilize modern parallel hardware

CryoEM structure of the human SLC4A4 sodium-coupled acid-base transporter NBCe1.

Na+-coupled acid-base transporters play essential roles in human biology. Their dysfunction has been linked to cancer, heart, and brain disease. High-resolution structures of mammalian Na+-coupled acid-base transporters are not available. The sodium-bicarbonate cotransporter NBCe1 functions in multiple organs and its mutations cause blindness, abnormal growth and blood chemistry, migraines, and impaired cognitive function. Here, we have determined the structure of the membrane domain dimer of human NBCe1 at 3.9 Å resolution by cryo electron microscopy. Our atomic model and functional mutagenesis revealed the ion accessibility pathway and the ion coordination site, the latter containing residues involved in human disease-causing mutations. We identified a small number of residues within the ion coordination site whose modification transformed NBCe1 into an anion exchanger. Our data suggest that symporters and exchangers utilize comparable transport machinery and that subtle differences in their substrate-binding regions have very significant effects on their transport mode

Phenotypic and functional characterization of corneal endothelial cells during in vitro expansion.

The advent of cell culture-based methods for the establishment and expansion of human corneal endothelial cells (CEnC) has provided a source of transplantable corneal endothelium, with a significant potential to challenge the one donor-one recipient paradigm. However, concerns over cell identity remain, and a comprehensive characterization of the cultured CEnC across serial passages has not been performed. To this end, we compared two established CEnC culture methods by assessing the transcriptomic changes that occur during in vitro expansion. In confluent monolayers, low mitogenic culture conditions preserved corneal endothelial cell state identity better than culture in high mitogenic conditions. Expansion by continuous passaging induced replicative cell senescence. Transcriptomic analysis of the senescent phenotype identified a cell senescence signature distinct for CEnC. We identified activation of both classic and new cell signaling pathways that may be targeted to prevent senescence, a significant barrier to realizing the potential clinical utility of in vitro expansion

DIGITALIZATION OF AGRICULTURAL COMPLEX WILL ALLOW TO ENSURE FOOD SECURITY

The role of digitalization of agriculture in increasing the competitiveness of the domestic agro-industrial complex (AIC) is indicated. In order to obtain an objective picture of the current state of the agro-industrial complex, the supply of the Republic of Uzbekistan with basic types of food has been analyzed and problems with the production of milk, beef, fruits and vegetables of the protected ground have been identified. It is noted that currently Uzbekistan is actively implementing import substitution strategies in the sectors of the national economy, including in the agricultural sector. The main purpose of the functioning of the domestic agro-industrial complex is determined ensuring food security parameters for the population of Uzbekistan. Investigated actual questions about how to achieve foodstuff - governmental self-sufficiency, the solution of which should be carried out in conjunction with an increase in the competitiveness of the Patriotic governmental APC. Emphasis is placed on the need to transfer agricultural production to the ecological and economic foundations of management and the rational distribution of the use of all types of resources. In each region of the country, it is recommended that the soil, climatic and economic potential of the territory be assessed in order to identify food self-sufficiency priorities for basic types of food. The development of the organizational and economic mechanism for the formation of competitive advantages of the agro industrial complex makes it possible to develop agricultural production on an innovative basis and ensure food safety at the state level in the long term. The factors of increasing the competitiveness of the agro-industrial complex were identified: economic soil fertility, used agricultural land, optimization of the structure of sown areas, systematic development of feed production and livestock production, digitalization of agriculture, etc. The problems of the insufficient prevalence of digital technologies in agriculture are analyzed. Substantiates the role of digitalization and to achieve the parameters of Prodo -food security. The results of the study can be used to improve the mechanism for ensuring food security of the population of Uzbekistan

Jumping Evaluation of Nested Regular Path Queries

International audienceNested regular path queries are used for querying graph databases and RDF triple stores. We pro- pose a new algorithm for evaluating nested regular path queries on a graph from a set of start nodes in combined linear time. We show that this complexity upper bound can be reduced by making it de- pendent on the size of the query’s top-down needed subgraph, a notion that we introduce. For many queries in practice, the top-down needed subgraph is way smaller than the whole graph. Our algo- rithm is based on a novel compilation schema from nested regular path queries to monadic datalog queries. Its complexity upper bound follows from known properties of top-down datalog evaluation. As an application, we show that our algorithm permits to reformulate in simple terms a variant of a very efficient automata-based algorithm proposed by Maneth and Nguyen that evaluates navigational path queries in datatrees based on indexes and jumping. Moreover, it overcomes some limitations of Maneth and Nguyen’s: it is not bound to trees and applies to graphs; it is not limited to forward navigational XPath but can treat any nested regular path query and it can be implemented efficiently without any dedicated techniques, by using any efficient top-down datalog evaluator. We confirm the efficiency of our algorithm experimentally based on an implementation with LogicBlox

Influence of cavitation on pressure pulsation through impeller of large pumps

The article provides the main recommendations for studying the processes of cavitation development on the models of pumping units OPV-10-260 and V 20-13/45 with an impeller diameter Dr = 250 mm. The nature of the effect of cavitation depends on forms of pressure pulsation. The purpose of this work is to study abrasive-cavitation erosion of large pumps. The research objectives are to develop a methodology for calculating their operating modes, taking into account the minimum deterioration of working parts. Strongly developed cavitation leads to disruption of regular pulsations and an increase in the swing of the high-frequency component. Investigations of operating mode of pumps with deterioration of elements of flow section were carried out, and the characteristics of materials for the manufacture of hydromechanical equipment for resistance to cavitation deterioration were refined. According to experiments, the influence of pressure on the pressure fluctuation range begins to significantly affect if the pump pressure is less than 5 m. The nature of the effect of cavitation depends on the forms of pressure pulsation. The complexity of composition, high cost of high-alloy steels, and non-ferrous alloys make it irrational to use them in massive parts operating under cavitation-abrasive conditions. It is recommended to use the developed dependencies on machine water elevating systems to reduce deterioration by improving the quality of impeller materials