DEVELOPMENT OF A METHOD FOR MODELLING DELAY PROPAGATION IN RAILWAY NETWORKS USING EPIDEMIOLOGICAL SIR MODELS

For railway systems belonging to network industries with high fixed costs, it is important to increase the use of the network capacity to reduce the average cost of cargo and passenger transport services. The degree of using the capacity of the railway network sections or even the network overload depends on the system properties of the reliability and stability of the train schedule. In the conditions of daily train operations, exogenous train delays occur and cause the delay propagation among other trains in the network. Despite the importance of knowing the parameters of such delays’ propagation in the railway network, methods to assess the vulnerability of the railway system are still insufficient. This problem is especially difficult for railway systems in which there is mixed movement of passenger and cargo trains in the same infrastructure and most cargo trains do not follow the schedule. This makes it impossible to provide detailed calculations of the delay propagation in the existing train schedules. That is why a study of complex dynamic processes of propagation of successive train delays at the macrolevel of the railway network is a relevant and very promising area of research.

The results of the simulation of a multi-element chain of grain supply by the rail and water multimodal route were shown. Mathematical substantiation of the optimization problem was presented. The minimum cargo delivery time was selected as the optimization criterion. The limits for the admissible use (loading) of fleets of transport units of railroad and water transport were selected as optimization constraints. The optimization model is a multi-parametric problem of stochastic programming. The objective function of the model was represented in implicit expression. The search for the solution of the optimization model was performed using experiments with the developed simulation model.
The simulation model is based on the discrete-event and agentbased principles, it simulates the interaction of two railroad and one sea transport and technological lines, as well as terminal points of accumulation, storage, and reloading of cargo batches. One ton of wheat grain acts as a part of the cargo module.
The simulation model was developed in AnyLogic RE (USA) and Java SE (USA) environments. The algorithm of the simulation model involves the interaction of populations of agents of transport junction points; agents of transport and technological lines; populations of agents of fleets of transport units; agents of information orders for transportation. The model was implemented using the example of the actual process of grain supply from Ukraine to Egypt.
The model was studied using the integer optimization method. As a result of experiments, the optimal values of the required stock of cars, locomotives, and naval vessels were established. In addition, the required capacity of granaries at the shipping stations and seaports' terminals, as well as the necessary capacity of track development of railroad stations, were found. The established average delivery time was within 185 hours.

Mykola Tsiuman
National Transport University, Kyiv, Ukraine ORCID: http://orcid.org/0000-0003-2537-8010 Andrii Loboda National Transport University, Kyiv, Ukraine ORCID: http://orcid.org/0000-0002-6956-3288 Motor transport is the main consumer of energy resources in most countries. Atmospheric conditions, along with the vehicle de- sign, its technical condition, driver's skill, road, and transport conditions significantly affect fuel consumption. However, in mathematical modeling, they are often taken into account by average values which can affect the accuracy of the results.
The nature of the relationship between ambient temperature and fuel consumption by city diesel buses was established on the basis of experimental and analytical studies. According to the results of the analysis of experimental data, it was found that this relationship is described by polynomial regressions of the second order. The accuracy of the regression model was confirmed by Fisher's test for two city routes.
Analytical studies of the effect of air density, rolling resistance, transmission efficiency, and all three factors together on fuel consumption were performed using mathematical modeling using the Physical Emission Rate Estimator methodology. It was found that rolling resistance and transmission efficiency have the greatest impact on fuel consumption. In both cases, the difference between the highest and lowest estimated value was 2.5 %. However, in absolute units, the difference is greater by 0.2 l/100 km for rolling resistance.
The obtained results can be used in mathematical models of vehicle movement, in particular city buses, to take into account the dynamics of changes in fuel consumption depending on the ambient temperature. They will also be useful in mathematical models for determining harmful emissions to calculate fuel consumption at various ambient temperatures.
Keywords: fuel consumption, ambient temperature, city diesel buses, experimental data. The life cycle of a passenger ship consists of such stages as designing, construction, operation, modernization, and disposal. Modernization includes a certain variety of operations on the vessel upgrading and thus contributes to the extension of the vessel life cycle. It is possible to determine the types, scope, and cost of operations for each vessel under consideration after analyzing its technical condition. It is advisable to alternate the operations of direct and indirect influence on the would-be profit from vessel operation when compiling a list of necessary modernization operations. Those vessels that as a result of preliminary calculations will not bring profit after modernization should not be included in the modernization plan.
Modernization is not able to replace shipbuilding as the main way to renew the fleet. However, under conditions of limited monetary funds, it should be used to smooth the need for new vessels.
The optimal distribution of funds between the groups of operations on vessel modernization was determined using a mathematical model. Objective function maximizes the profit gain from modernization operations. The controlled system in this case is a passenger ship. The state of the system before each step is characterized by the number of still undistributed funds. As a result of solving the problem, a shipowner receives an answer regarding the amount of funds available for him, the groups of operations on the passenger ship modernization in which to invest to have the highest profit gain.
Thus, the strategy of modernization of passenger ships by optimal distribution of funds is based on determining the types and volume of operations, their cost, utility, the ability to gain profit from the operation of a modernized vessel. It is also based on the optimization problem of allocating funds to modernization, provided they are limited.
Keywords: modernization, passenger ship, money distribution, dynamic programming, life cycle. A comprehensive study of the process of decomposition and segregation of infrastructure project management elements using a mono-template under the influence of changes and safety-oriented management was carried out. The use of project, program and portfolio management tools made it possible to generalize the process of structural decomposition of infrastructure projects and features of segregation of management elements using a mono-template and provisions of safety-oriented management. This is important because of the peculiarities of the formation and planning of infrastructure projects: content, structure requirements and values, among which safety is the key. Thus, a conceptual schematic model of a mono-template in safety-oriented management is developed, which includes three blocks of project management. This made it possible to improve the planning process of infrastructure projects. The schematic model is developed and the application of the filter system of elements and parameters of infrastructure project management in safety-oriented management is proposed. The system allows carrying out the process of segregation of the necessary elements and parameters of infrastructure project management with the use of a mono-template. The influence and consequences of application on the basis of project parameters are described. A formalized model of the segregation process of infrastructure project management elements and parameters at the level of a mono-template in safety-oriented management is presented. The process of transition of structurally decomposed management elements and parameters through the filter system is described. In the course of this process, the project factors of proactive management, internal project environment, changes and system resistance affect the formed structurally decomposed blocks of a mono-template. The models developed in the study complement the project management tools and provide an opportunity to carry out the process of planning infrastructure projects at a high-quality level.
Keywords: infrastructure project, segregation, filter, impact of changes, project decomposition, safety-oriented management, monotemplates. Risk-based approaches are a feature of the modern quality management system. A method of optimization of product quality inspection plan by the risk of non-conformity slippage is proposed. The method is based on a risk ranking matrix, criteria of the failure mode and effects analysis (FMEA), block classification of inspection plans, approaches to non-conformity prediction, and probability multiplication theorem for independent events.
The risk of non-conformity slippage was defined as a criterion of inspection plan optimization. The proposed method allows determining the acceptability of the risk, with 100 % quality inspection, in case of abandoning the inspection operation, the possibility of applying sampling and minimum sampling volumes necessary to ensure an acceptable risk level. Relationships were derived to determine the minimum required number of inspected units out of 1,000, with an acceptable risk level in product quality inspection. The initial data for the calculation are the main characteristics of the inspection plan: the probability of the object conformity with the requirements for the controlled quality characteristic, the probability of not detecting non-conformity with the provided inspection method, the rate of non-conformity slippage, which ensures an acceptable risk level. The formula allows calculating the minimum sampling volume that provides an acceptable level of non-conformity slippage risk during the implementation of the product quality inspection plan (QIP).
The proposed method was tested on the inspection plan for welds of air tanks of the railway car braking system. It is possible to abandon the original 100 % inspection plan and apply sampling, which provides an acceptable level of non-conformity slippage risk. This allows reducing the volume and costs of inspection by 18 %.
Keywords: quality inspection planning, non-conformity risk, probability rank, FMEA, quality management. 6/3 ( 108 ) 2020 glazed windows within the framework of a virtual instrumentbuilding enterprise (VIE) that produces solar energy complexes. It is shown that improving the efficiency in solving the tasks related to managing the quality of VIE products necessitates the application of an ontological engineering toolset to create a unified knowledge space that would cover the manufacturing phase of a product's life cycle. The methodical basis for making an ontological informationanalytical system (OIAS) to manage product quality was the tool platform "TODOS" (Ukraine) whose means were used to synthesize a set of ontological models that make up the intelligent core of OIAS. The OIAS knowledge-based inference procedure has been described when making a decision about a deviation in the manufacturing process that led to the emergence of damage. This procedure implies the implementation of direct and reverse inference based on the knowledge in the ontological environment and makes it possible to identify the sources of defects and damage and generate a solution to eliminating these sources. Procedures have been devised to assess the effectiveness of the development and application of OIAS to automate the quality management of multi-layered double-glazed windows. These procedures employ a set of indicators that reflect both the technical and economic components of the quality control process. It has been shown that during 2019 a typical subcontractor enterprise that applied the developed system managed to reduce the number of defective products by about 73 %. Further research areas have been identified, including the development of methodical means and, based on them, the toolsets for the deployment of industrial ontological quality management systems.