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1

A method for calculating the technical readiness of aviation refuelling vehicles

Ziółkowski Jarosław, Oszczypała Mateusz, Lęgas Aleskandra, Konwerski Jakub, Małachowski Jerzy

Eksploatacja i Niezawodność

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2024

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Vol. 26, no. 3

art. no. 187888

EN

In the paper a mathematical model of the process of operating aviation refuelling vehicles supplying fuel to aircraft before flight was developed. The present work is a continuation and supplement to the model contained in [52]. The phase space of the process under study was mapped by a 7-state directed graph of the operation process. To calculate the technical readiness index (𝐾𝑔𝑡 ) Markov chains and processes were used. Also, in Section 3, Results and discussions, optional methods for determining the technical readiness coefficient of a vehicle were provided (𝑘𝑔𝑡 ) , based on the total time of the object in individual operating states. This is an alternative in a situation where the analysed process cannot reach a stable average state indefinitely. Two types of measures were used to determine the readiness, i.e. border probabilities and average times of the object in individual states. In both cases, the basis was statistical databases with operational vehicle data, which enabled the calculation of the readiness index and coefficient.

2

Semi-Markov approach for reliability modelling of light utility vehicles

Oszczypała Mateusz, Ziółkowski Jarosław, Małachowski Jerzy

Eksploatacja i Niezawodność

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2023

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Vol. 25, no. 2

art. no. 161859

EN

Vehicles are important elements of military transport systems. Semi-Markov processes, owing to the generic assumption form, are a useful tool for modelling the operation process of numerous technical objects and systems. The suggested approach is an extension of existing stochastic methods employed for a wide spectrum of technical objects; however, research on light utility vehicles complements the subject gap in the scientific literature. This research paper discusses the 3-state semi-Markov model implemented for the purposes of developing reliability analyses. Based on an empirical course of the operation process, the model was validated in terms of determining the conditional probabilities of interstate transitions for an embedded Markov chain, as well as parameters of time distribution functions. The Laplace transform was used to determine the reliability function, the failure probability density function, the failure intensity, and the expected time to failure. The readiness index values were calculated on ergodic probabilities.

3

Assessment of options to meet transport needs using the MAJA multi-criteria method

Małachowski Jerzy, Ziółkowski Jarosław, Oszczypała Mateusz, Szkutnik-Rogoż Joanna, Lęgas Aleksandra

Archives of Transport

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2021

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Vol. 57, iss. 1

25--41

EN

The problem of choosing the way to move people is often encountered both in scientific research and in everyday life. The difficulty of this process depends on the availability of many variants and the pursuit of satisfying transport needs at the minimum cost, in the shortest possible time and in the most comfortable conditions. The publication presents a decision problem of choosing the best transport option using multi-criteria methods. At the beginning authors presented the widely used methods of solving decision problems in the literature. Subsequently, based on the example of the Warsaw-Wroclaw connection, the MAJA multi-criteria assessment method algorithm was analysed. Both road, rail and air transport options were considered. Six possible variants of solutions were indicated, which were assessed in three sub-criteria: cost, time and comfort of travel. Then, the results of the analysis were compared with the results obtained using other multi-criteria decision-making support methods, i.e. ELECTRE I, AHP, TOPSIS, PROMETHEE, SAW, PVM. The considered methods were divided according to the way the result was presented, as a result of which the methods based on the relation of superiority (which included the MAJA method) and methods using ranking were distinguished, and then an intra-group comparison was made. On the basis of the constructed compliance matrix of the relation of superiority, it was found that domination methods exhibited convergence of the obtained results. However, in order to compare the convergence of the results of the ranking methods, the Spearman's linear correlation coefficient was used. The applied MAJA multi-criteria method has made it possible to determine non-dominated solutions considered optimal taking into account the adopted weights of criteria and compliance and non-compliance thresholds. Its unquestionable advantage is the possibility of using many partial criteria expressed in different measurement units. In the presented example, the best options were the premium express rail transport and airplane. The summary defines the direction of further research and possibilities of modification of the presented method.

4

Planning supplies in the enterprise in the aspect of reliability

Ziółkowski Jarosław, Żurek Józef, Lęgas Aleksandra, Szkutnik-Rogoż Joanna, Oszczypała Mateusz, Dobrzyński Krzysztof

Journal of KONBiN

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2020

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Vol. 50, iss. 4

251--268

EN

The article presents the example of material needs planning (MRP) methodology in a production company. The example assumes the production technology of three independent products A, B and C exhibiting structural modularity. For calculations, a methodology should be developed for describing products with such a structure that reflects the relationships of individual components used to prepare a delivery schedule. The Microsoft Excel spreadsheet was used as the calculation tool.

PL

W artykule przedstawiono na przykładzie metodykę planowania potrzeb materiałowych (MRP) w przedsiębiorstwie produkcyjnym. W przykładzie założono technologię wytwarzania trzech niezależnych wyrobów A, B i C wykazujących modułowość strukturalną. Do obliczeń należy opracować metodykę opisu wyrobów o takiej strukturze odzwierciedlającą zależności poszczególnych elementów składowych, służących do sporządzenia harmonogramu dostaw. Jako narzędzie służące do obliczeń wykorzystano arkusz kalkulacyjny MS Excel.

5

Application of the Bloch-Schmigalla Method to Optimize the Organization of the Process of Repairing Unmanned Ground Vehicles

Małachowski Jerzy, Ziółkowski Jarosław, Szkutnik-Rogoż Joanna, Lęgas Aleksandra, Oszczypała Mateusz

Advances in Science and Technology. Research Journal

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2020

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Vol. 14, no 3

39--48

EN

The aim of this paper was to present the application of the Bloch-Schmigalla method in order to deploy work stations and create a military equipment repair model under field conditions. Proper allocation of repair stations is of crucial importance from the point of view of a given material’s flow optimization. The aim of proper object allocation is such use of space that enables continuous, efficient and safe work. On the basis of numerical data, the advantages of using the Bloch-Schmigalla method for the optimal location of repair positions were presented. The proposal to optimize the organization of the repair process with using the Bloch-Schmigalla method entails multiple advantages e.g. decreasing the volume of transport activity size or time saving resulting from the rational arrangement of repair stations for unmanned ground vehicles.