The work highlights the issue of using the modeling method in inventory management of hierarchical logistics systems. The issue of the necessity of inventory management modeling as one of the key parameters of distribution logistics is substantiated. It has been proven that the hierarchical logistics system can generate flow processes according to Poisson’s law, which makes it possible to apply the theory of mass service systems in the formalization of the processes of incoming supplies of resources to replenish the stocks of the logistics center with further distribution of flows among regional branches. This method is based on obtaining optimal characteristics of the intensity of supply of resources in the section of a specific nomenclature, subject to restrictions on available working capital and the formation of a reserve stock for maintenance of repair works.

The paper substantiates the need of usage mathematical and computer modelling in data analysis in assessing with the functioning of logistic processes and systems. Based on the analysis of existing approaches, the peculiarities of using an integrated method of mathematical and computer modelling in order to effective set up and implement a process research experiment are revealed. The logistic system is formalized within the supply of material and technical resources by a centralized method of flow distribution and transfer of management influence from the highest level of the hierarchy to the lower levels such as branches or separate units. Formal identification of the logistic system of supply of material and technical resources is based on the separation of the main factors of the system and the limits of their impact. The main stages of modelling the functioning of logistics processes are specified, which is the basis for clarifying the algorithmic features of the computer experiment. It is stipulated that one of the main approaches to the study of these systems is modelling based on the use of methodological principles of queuing theory, which is based on modelling the flow characteristics of processes, orders and the discipline of their service. The procedure for determining the main characteristics of the system is focused on conducting computer simulations by setting up a computer experiment aimed at simulating the behaviour of the system and its evaluation. Probabilistic estimates of the queuing system are obtained under stationary operating conditions, in the established mode, which achieves limiting the impact of the conditions of the initial state. Emphasis is placed on combining simulation modelling as one of the approaches of computer modelling with elements of optimization solutions that can be obtained as an analytical solution to specific applications of logistics of varying complexity, in particular, inventory management.

The work highlights the issue of using the modeling method in inventory management of hierarchical logistics systems. The issue of the necessity of inventory management modeling as one of the key parameters of distribution logistics is substantiated. It has been proven that the hierarchical logistics system can generate flow processes according to Poisson’s law, which makes it possible to apply the theory of mass service systems in the formalization of the processes of incoming supplies of resources to replenish the stocks of the logistics center with further distribution of flows among regional branches. This method is based on obtaining optimal characteristics of the intensity of supply of resources in the section of a specific nomenclature, subject to restrictions on available working capital and the formation of a reserve stock for maintenance of repair works.

Purpose. The article is devoted to the issues of system research in the field of agricultural logistics. The necessity of agricultural logistics research on the basis of a systematic approach, the essence of which is manifested in the idea of studying the relationship between the individual parts of the logistics object with a mathematical model. The main principles of the system approach in the management of agricultural logistics systems are recognized as: consistency, decomposition, modeling, uncertainty, efficiency, consistency, sufficiency, purposefulness, alternativeness. The integrity and uniqueness of agricultural logistics systems is due to the cause-and-effect relationship, which manifests itself as a purposeful action of individual elements and subsystems and has a sustainable economic structure. The structural characteristics of agricultural logistics systems are highlighted in the process of synthesis of their components from the highest to the lowest level of the hierarchy, on the basis of which the conclusion about the hierarchical construction of agricultural logistics systems is made. It was found that the formalization of the model of agricultural logistics system is due to the finite level of specification of the number of parameters, blocks and constraints. Most of the properties of agricultural logistics system are probabilistic. Variability in the behavior of the agricultural logistics system arises due to external influences, the critical level of which exceeds the expected value. Thus, changes in the characteristics of each level of the agricultural logistics system must be coordinated with each other. A statement is formed about the completeness of decision-making at different levels of the hierarchy of the system, which results in the implementation and coordination of functions to achieve the goal. The behavior of the system is formed on the basis of the allocation of a particular alternative from a particular set of alternatives in accordance with the response to external influences. Methodology. The study is based on the use of such general scientific methods as: analysis, synthesis and analogy. For the system approach it is important to determine the structure of the system - a set of relations between the elements of the system, reflecting their interaction. The purpose of the work is to study the principles of the system approach in the management of processes and systems of agricultural logistics. Practical implications. The practical value of the work lies in identifying the main systemic cause-and-effect patterns emerging in the agro-industrial complex environment and potentially determining the structure of agricultural logistics systems. The agro-industrial complex is characterized by increasing rates. Grain and oilseed crops, vegetable oils and meal are the basis of external supplies, which in total account for more than 80% of the volume. One of the main problems of the agricultural sector is logistics, which must solve the issues of preservation of harvested products, transportation and sales to the end consumer. The functioning of agricultural logistics is reflected in the export potential of Ukraine, and at the same time it replenishes the budget. The share of exports of food products and agricultural products in the total exports of Ukraine in 2020 was 45.1%. Grain crops (42.4%); oils (25.6%); oilseeds (8.1%) account for the share of exports. There is a real need for terminals, both maritime and river terminals. These are all system characteristics of agricultural logistics A systematic study of agricultural logistics is a key element on the basis of which the practical organization of these systems should be considered as a source of long-term growth of the agricultural sector. Value/originality. The peculiarity of this study is the transformation, implementation of the basic principles of the system approach and the theory of systems to the industry specifics of agro-logistics. On the basis of influencing system factors of agricultural production, the properties of agro-logistic systems and their targets are highlighted and generalized.

Purpose. The logistics of the agrarian sector covers the study of the management processes of material, informational and their consequential financial flows that have formed on the market of agricultural products and are distributed from its producer to consumers. The logistics chain is built starting from the planning processes of the production cycle of agricultural products and ending with the sale to the final consumer. Building an effective logistics system includes cost control, effective management of materials and finished products storage, provision of information support, development of delivery traffic diagram, service provision, formation of a freight network, etc. The purpose of the work is the development of mathematical methods and models for the systematic analysis of the functioning of the regional logistics system of providing agricultural material and technical resources. Methodology. To solve it in the proposed monograph, based on the study of the functioning of the modern logistic system of material and technical support, the methods of system analysis, the theory of mass service and the theory of stock management are applied. This allows to study in detail all aspects of external and internal connections, create a model of the system functioning, adequately assess its implementation, determine the optimal working conditions and, at the same time, forecast the financial characteristics of the activity. To solve this problem, a number of tasks are set in the paper. They take into account a large number of random factors, complex interactions of task parameters, non-linear dependencies, the influence of time delays on the overall functioning of the system, the formation of sales volumes and supplies of material resources. The models and methods of problem solving are original both from the point of view of research methodology and from the point of view of predicting the implementation of such systems. Practical implications. The greatest effect of logistics is achieved in integrated supply chains, which are implemented on the basis of large enterprises through the integration of raw material bases and industrial processing enterprises. When studying logistics support, in addition to the issue of transportation, considerable attention should be paid to the infrastructure for product storage. When organizing technical service and specific problems related to this, it is possible to solve such tasks as creating a competitive environment, certain changes in management; elimination of the shortage of material and technical resources due to the increase in production volumes, the introduction of new progressive technologies; creating a market for services and used equipment. Value/originality. The system of material and technical support is an organizational and management mechanism of interconnected actions of economic formations adapted to market conditions, aimed at timely and rhythmic provision of commodity producers with agricultural machinery, spare parts, fuel and lubricants. Under market conditions, their activity is based on a contractual basis and is more influenced by various external factors. Therefore, the problem arises of choosing such a mechanism of operation of logistics systems that form a regional system of material and technical support, in which their activity will be profitable and profitable.