MOST CITED
Update: 2021-07-01
Task „Implementation of procedures ensuring the originality of scientific papers published in the quarterly „Eksploatacja i Niezawodność – Maintenance and Reliability” financed under contract 532/P-DUN/2018 from the funds of the Minister of Science and Higher Education for science dissemination activities.
Mariusz Izdebski
Zastosowanie modelu konfiguracji łańcucha dostaw do oceny niezawodności Realizacji procesów logistycznych
W artykule przedstawiono podejście do oceny niezawodności procesów logistycznych realizowanych w łańcuchach dostaw w aspekcie strat czasu wynikających z wyboru wariantu realizacji przepływów materiałowych w łańcuchu dostaw. Na potrzeby tych badań opracowano model matematyczny łańcucha dostaw, tj. określono parametry problemu badawczego, zmienne decyzyjne, ograniczenia oraz kryteria oceny. Sposób oceny niezawodności systemu został przedstawiony w postaci schematu. Algorytm został zweryfikowany na podstawie danych eksperymentalnych. W celu oceny niezawodności procesów logistycznych dla przykładowego łańcucha dostaw opracowano model symulacyjny wyznaczający straty czasu w elementach punktowych i liniowych badanego łańcucha. Straty czasu podyktowane są opóźnieniami w ruchu drogowym wynikającymi z kongestii ruchu na poszczególnych odcinkach trasy i węzłach drogowych oraz opóźnieniami w elementach punktowych łańcucha dostaw.
The use of a supply chain configuration model to assess the reliability of Logistics processes
The article presents an approach to assessing the reliability of logistics processes implemented in supply chains in terms of time losses resulting from the selection of a variant of material flows in the supply chain. In order to define this indicator, a mathematical model of the supply chain has been developed, i.e. the parameters of the research problem, the decision variables, the constraints and the evaluation criteria. The method of evaluating the reliability of the system is presented in diagram form. The algorithm was verified based on experimental data. In order to evaluate the reliability of the logistic processes for the sample supply chain, a simulation model was developed that determines the time losses in the points and linear elements of the examined chain. Time losses are dictated by traffic delays resulting from traffic congestion on particular sections of the route and road junctions and delays in point elements in the supply chain.
Planning and management of aircraft maintenance using a genetic algorithm
The aim of the article was to develop a tool to support the process of planning and managing aircraft (ac) maintenance. Aircraft maintenance management has been presented for scheduled technical inspections resulting from manufacturers’ technical documentation for ac. The authors defined the problem under investigation in the form of a four-phase decisionmaking process taking into account assignment of aircraft to airports and maintenance stations, assignment of crew to maintenance points, setting the schedules, i.e. working days on which aircraft are directed to maintenance facilities. This approach to the planning and management of aircraft maintenance is a new approach, unprecedented in the literature. The authors have developed a mathematical model for aircraft maintenance planning and management in a multi-criteria approach and an optimisation tool based on the operation of a genetic algorithm. To solve the problem, a genetic algorithm was proposed. The individual steps of the algorithm construction were discussed and its effectiveness was verified using real data.
Risk assessment for rail freight transport operations
The aim of this article is to assess the risk of performance of rail freight transport on the basis of an analysis of identified risk areas based on statistical data on the causes of accidents that occurred on the lines of railway transport in Poland. A critical review of selected scientific studies relating to the risk assessment process for identified areas of the railway system has been undertaken. Based on statistical data, the authors analysed the causes of accidents on railway lines in 2019 in Poland and determined the probability of occurrence of a given cause. In addition, the article calculates the probability of vehicle delays for different emergency situations occurring in the performance of rail freight transport operations. This enabled the authors of the article to carry out a risk assessment of freight train delays on railway lines.
Evaluation of efficiency and reliability of airport processes using simulation tools
The purpose of this paper is to evaluate the efficiency of airport processes using simulation tools. A critical review of selected scientific studies relating to the performance of airport processes with respect to reliability, particularly within the apron, has been undertaken. The developed decision-making model evaluates the efficiency of airport processes in terms of minimizing penalties associated with aircraft landing before or after the scheduled landing time. The model takes into account, among other things, aircraft take-offs and landings and separation times between successive aircraft. In order to be able to verify the correctness of the decision-making model, a simulation tool was developed to support decision making in the implementation of airport operations based on a genetic algorithm. A novel development of the structure of a genetic algorithm as well as crossover and mutation operators adapted to the determination of aircraft movement routes on the apron is presented. The developed simulation tool was verified on real input data.
Selection of a fleet of vehicles for tasks based on the statistical characteristics of their operational parameters
The article presents a method of selecting a fleet of vehicles with a homogeneous structure for tasks based on the statistical characteristics of their operational parameters. The selection of a vehicle fleet for tasks is one of the stages of vehicle fleet management in transport companies. The selection of a vehicle fleet for tasks has been defined as the allocation of a vehicle model to a given company, which is associated with the unification of the vehicle fleet to one specific type. The problem of selecting a fleet of vehicles has been presented in a multi-criteria approach. The operational parameters assessing the selection of vehicles for the tasks are mileage and the number of days to the first and subsequent failure, and vehicle maintenance costs. The developed method of selecting a fleet of vehicles for the tasks consists of two stages. In the first stage, the average operating parameter values are determined using statistical inference. In the second stage, using the MAJA method, a unified model of the fleet of vehicles operating in the enterprise is established.