Wyniki wyszukiwania - BazTech

1

The impact of the intermodal terminal operation strategy on container train loading duration

Kłodawski Michał, Nehring Karol, Jachimowski Roland, Lipińska Justyna

Transport Problems

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2024

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T. 19, z. 2

163--176

EN

The aim of the article was to study the impact of various real-life factors determining the container train loading process duration. Various strategies of the crane operation were considered. Among the factors influencing the train loading duration, railcar hitching pin configuration, container weight, railcar capacity, and arrangement of containers in the storage yard were considered. The FlexSim simulation model of the container terminal was developed, covering the storage yard and the railway track. The analysis shows that the number of containers collected directly from the storage yard has the greatest impact on the train loading duration.

2

Modelling of e-commerce packing line in the warehouse – case study

Kmiecik Mariusz

Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

|

2023

|

z. 173

329--344

EN

Purpose: The purpose of this paper is to create a simulation model of a packing line in an e-commerce activity from the perspective of a logistics operator, along with identifying recommendations for further model improvement as part of digital transformation. Design/methodology/approach: This paper uses results obtained by simulation analysis of a computer model of a process built in BPMN 2.0 notation. Data for the model was collected from process analysis, analysis of data obtained from WMS and sensors on the packaging line and from participant observation in the process. Findings: Based on the analysis, it can be concluded that the logistics operator is able to create a simulation model of the process and optimise its operations using the simulation results. The model presented can also be the basis for building a Digital Twin in the distribution network for e-commerce flows. Practical implications: The logistics operator can extend its package of services to include the construction of simulation models and, in future, can also take on the task of creating value for the network on the basis of the Digital Twin created. Originality/value: The paper presents a real-life case study related to the first phase of Digital Twin implementation, namely the creation of a simulation model to create value in the flows and improve the logistics processes involved in serving the e-commerce market.

3

Diagnostics of electric drive electric vehicle with valve motor

Borodenko Yuriy, Arhun Shchasiana, Hnatov Andrii, Kunicina Nadezhda, Bisenieks Martins, Migal Vasiliy, Hnatova Hanna

Przegląd Elektrotechniczny

|

2023

|

R. 99, nr 6

32--38

EN

The reliability, safety and economy of the electric vehicle depend on the operation of the electric drive. Diagnosing malfunctions at startup avoid an accident by turning off the system power. Idle testing prevents an accident that may occur while driving. Monitoring the technical states of the electric power supply during the transport process provides an emergency operation mode by redistributing power between its elements. This model presents the results of testing the method of spectral analysis of electrical processes occurring in the power circuit of the electric power supply simulation model. The information content of spectrograms, as a characteristic of the diagnostic parameter, is determined by the options for setting up the FFT analyzer. These options are configured to a maximum frequency switching converter. And other is the sampling period of the spectral characteristic, and the fundamental frequency is selected as multiples of the rotation speed of the electric motor and the switching frequency of the inverter, taking into account the number of phases of the machine. This paper deals with faulty states of electric drive. It is associated with the failure of a functional element, the circuit (breakage or closure) or the deviation of the element parameters from the nominal values. In the first case, the structural identification problem, the system's state, is considered the second - parametric.

PL

Od działania napędu elektrycznego zależy niezawodność, bezpieczeństwo i ekonomia pojazdu elektrycznego. Diagnozowanie usterek podczas uruchamiania pozwala uniknąć wypadku, wyłączając zasilanie systemu. Testy na biegu jałowym zapobiegają wypadkom, które mogą wystąpić podczas jazdy. Monitorowanie stanów technicznych zasilania elektrycznego podczas procesu transportu zapewnia awaryjny tryb pracy poprzez redystrybucję mocy pomiędzy jej elementy. Model ten przedstawia wyniki badań metody analizy spektralnej procesów elektrycznych zachodzących w obwodzie mocy modelu symulacyjnego zasilania elektrycznego. Zawartość informacyjna spektrogramów, jako cecha parametru diagnostycznego, jest określona przez opcje konfiguracji analizatora FFT. Opcje te są skonfigurowane do maksymalnej przetwornicy częstotliwości przełączania. Drugim jest okres próbkowania charakterystyki spektralnej, a częstotliwość podstawowa jest wybierana jako wielokrotność prędkości obrotowej silnika elektrycznego i częstotliwości przełączania falownika z uwzględnieniem liczby faz maszyny. Artykuł dotyczy stanów wadliwych napędu elektrycznego. Jest to związane z uszkodzeniem elementu funkcjonalnego, obwodu (przerwanie lub zamknięcie) lub odchyleniem parametrów elementu od wartości nominalnych. W pierwszym przypadku problem identyfikacji strukturalnej, stan systemu, jest uważany za drugi - parametryczny.

4

Analysis of the country’s energy efficiency using ODEX indicators

Sowiński Janusz

Przegląd Elektrotechniczny

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2023

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R. 99, nr 6

154--157

EN

One of the priority tasks in the country's energy economy is the improvement of energy efficiency. Sectoral energy consumption indicators enable the monitoring of the country's energy economy. The analysis of sectoral ODEX indicators is essential for predicting energy savings. The courses of the ODEX indicators and energy efficiency indicators were modeled with stochastic differential equations. Solving the equations using the Euler method enables the simulation of curves in the medium-term horizon. The results of simulation were presented.

PL

Jednym z priorytetowych zadań w gospodarce energetycznej kraju jest poprawa efektywności energetycznej. Sektorowe wskaźniki zużycia energii umożliwiają monitorowanie gospodarki energetycznej kraju. Analiza sektorowych wskaźników ODEX jest niezbędna do prognozowania oszczędności energii. Przebiegi wskaźników ODEX i wskaźników sektorowych efektywności modelowano stochastycznymi równaniami różniczkowymi. Rozwiązanie równań metodą Eulera umożliwia symulację krzywych w horyzoncie średniookresowym. Przedstawiono wyniki symulacji.

5

Use of the digital twin concept to optimize the production process of engine blocks manufacturing

Sujová Erika, Bambura Roman, Vysloužilová Daniela, Koleda Peter

Production Engineering Archives

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2023

|

Vol. 29, Iss. 2

168--174

EN

The aim of the paper is to present the concept of a digital twin (DT) as part of the Industry 4.0 strategy. In the form of a case study, a digital twin of a production line for the processing of engine blocks is presented, which will serve as a starting point for further research in the field of digitization of production processes. The research part describes the simulation model of the production line with the representation of the material flow as a basis for the creation of a digital twin. The simulation model was used to optimize the production processes of the engine block and to verify the increase in its productivity. A case study implemented through a digital twin enables testing and analysis of changes before they are introduced into real production.

6

Proces referencyjny jako narzędzie przyspieszające modelowanie symulacyjne procesów logistycznych

Pawlewski Paweł, Hoffmann Marta, Kegel Izabela, Krawczyk Klaudia, Kołodziej Agata

Zeszyty Naukowe Politechniki Poznańskiej. Organizacja i Zarządzanie

|

2022

|

Nr 85

189--204

PL

W przedsiębiorstwach realizowanych jest wiele procesów, które mają umożliwić osiągnięcie zdefiniowanych celów biznesowych. W dużej mierze są to procesy cykliczne, to znaczy takie, które się powtarzają i mają wyznaczony przebieg. Różnią się zazwyczaj szczegółami, takimi jak lokalizacja źródłowa i docelowa, lub miejscem występowania w systemie. Podczas modelowania w programach symulacyjnych różnice te znacznie wpływają na poziom zaawansowania modelu. W trakcie odzwierciedlania procesów w programach brakuje możliwości automatycznego działania – sztucznej inteligencji odpowiadającej za cykliczność. Celem tej pracy jest przedstawienie podejścia do modelowania - tzw. procesu referencyjnego, który pozwala na ułatwienie i skrócenie czasu projektowania procesów logistycznych w modelach symulacyjnych. Przedstawiono rozwiązanie, w którym definiuje się jedynie zasady wyboru tzw. lokalizacji pełniących funkcję buforów, pól odkładczych, a modelowane czynności procesu są generowane automatycznie. Zaproponowano zasadę pozwalającą na modelowanie według reguł losowych, wskazując dalsze kierunki prac badawczych związanych z regułami ilościowymi i czasowymi. W artykule przedstawiono również implementację tego rozwiązania w programie symulacyjnym LogABS.

EN

In enterprises, many processes are implemented to achieve the defined business goals. These are mainly cyclical processes, that is, processes that repeat and have a designated course. They usually differ in details, such as the source and destination, or where they appear in the system. When modeling in simulation programs, these differences significantly affect the advancement of the model. In the process of reflecting processes in programs, there is no possibility of automatic operation – “artificial intelligence” responsible for cyclicality. The aim of this work is to present an approach to modeling – the so-called reference process that allows one to simplify and shorten the design time of logistics processes in simulation models. A solution was proposed in which only the rules for selecting the so-called locations acting as buffers, storage fields, and modeled process activities are generated automatically. The proposed rule allows for modeling according to random rules, indicating further directions for research related to quantitative and time rules. The article also presents the implementation of this solution in the LogABS simulation program.

7

Krajowy model ciężarowego transportu drogowego na podstawie wyników badań TD-E

Naumov Vitalii, Szarata Andrzej, Vasiutina Hanna

Transport Miejski i Regionalny

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2022

|

nr 5

3--9

PL

Modele symulacyjne systemów transportowych są kluczowym narzędziem do rozwiązywania wielu zagadnień z zakresu zarządzania tymi systemami. Metodologie tworzenia tych modeli wykorzystują zestawy danych zarówno o infrastrukturze transportowej, jak i o popycie na dostawę towarów lub przewozy pasażerów, jednak w tym zakresie wiele czynników uwzględniano na podstawie przypuszczeń z powodu złożoności modelowanych obiektów. W niniejszym artykule opisano podejście do modelowania systemu przewozów towarowych transportem drogowym w skali całej Polski, w oparciu o dane uzyskiwane przez Główny Urząd Statystyczny na podstawie badania TD-E. Takie podejście pozwala uniknąć wielu przypuszczeń dotyczących popytu na przewozy towarowe, ponieważ parametry tego popytu są oszacowywane w oparciu o próbkę reprezentującą populację generalną – zbiór wszystkich podmiotów gospodarczych kraju generujących ruch towarowy. Podstawowe procedury w opracowanym podejściu do modelowania systemu transportu towarowego zaimplementowano w postaci skryptów w języku Python. W wyniku wykorzystania proponowanej metodologii uzyskano model ciężarowego transportu drogowego w skali całego kraju na podstawie danych badania TD-E z roku 2018. Ocenę adekwatności opracowanego modelu przeprowadzono w oparciu o wyniki Generalnego Pomiaru Ruchu z roku 2015 na podstawie współczynnika determinacji jako miary jakości. Uzyskany model charakteryzuje się zadowalającą jakością (wartość współczynnika determinacji wyniosła 0.62), która może być poprawiona po kalibracji funkcji oporu przestrzeni oraz udoskonalenia procedury rozkładu ruchu na sieć drogową.

EN

Simulation models of transport systems are a key tool for addressing many issues in the field of management of these systems. The methodologies for creating such models use data sets on both transport infrastructure and demand for the freights or passenger transport, however, many factors are considered based on assumptions due to the complexity. This article describes the approach to modeling the cargo transportation system for road transport in Poland based on data obtained by the Central Statistical Office from the TD-E survey. This approach avoids many assumptions about the demand as the demand parameters are estimated based on a sample representing the general population – a set of all economic entities generating freight traffic. Basic procedures in the developed approach have been implemented as Python scripts. As a result of the use of the proposed methodology, a country-wide road transport model was obtained based on the TD-E survey from 2018. The adequacy of the developed model was assessed based on the results of the General Traffic Survey from 2015. The obtained model is of satisfactory quality (the coefficient of determination equals 0.62), which can be improved after calibrating the space resistance functions and improving the traffic distribution procedure.

8

Opracowanie modelu rozpływu prądu w sieciach jezdnych dla innowacyjnego systemu odladzania

Skrzyniarz Marek, Kruczek Włodzimierz, Mike Kamil, Stypułkowski Piotr

Problemy Kolejnictwa

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2022

|

Z. 195

63--67

PL

Oblodzenie sieci trakcyjnej uniemożliwia skuteczne i efektywne odbieranie prądu z sieci trakcyjnej. Na skutek oblodzenia mogą wystąpić straty u przewoźników z powodu opóźnienia lub odwołania pociągów. Zdarzają się także przypadki uszkodzenia infrastruktury trakcyjnej oraz pantografów. Istniejące metody odladzania sieci trakcyjnej (mechaniczne, chemiczne i elektryczne) są obecnie nieefektywne. Z tego względu konieczne jest opracowanie nowej, elektrycznej metody, która uwzględni szczegółowy rozpływ prądu w sieci trakcyjnej. W artykule zaprezentowano model do obliczeń rozpływu prądu w sieci trakcyjnej oraz zmierzone, na podstawie rzeczywistych pomiarów, rezystancje wieszaków, elementów podwieszeń oraz uchwytów odległościowych do przewodów jezdnych.

9

A Quick-and-Dirty Method for assessing the Risk of Negative Aeration Effects of Shock Absorbers equipped with Shim Sliding Base Valves

Czop Piotr, Gniłka Jacek

Computer Assisted Methods in Engineering and Science

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2022

|

Vol. 29, no. 3

229--260

EN

This paper presents a quick-and-dirty method to assess the risk of negative aeration effects occurring in twin-tube hydraulic shock absorbers used in passenger cars at the early design stage. The method is intended to be implemented as an engineering calculation tool based on the computational fluid dynamics (CFD) two-dimensional (2D)/three-dimensional (3D) steady-state single-phase model. The CFD model was previously validated with the use of the particle image velocimetry (PIV) experiment. The negative aeration effect is a wellknown issue for automotive and railway shock absorbers manufacturers. It results in uncontrolled on-vehicle vibrations and the deteriorated shock absorber damping characteristic. The major aeration contributor in twin-tube hydraulic shock absorbers is the sliding shim intake valve, which requires design optimization to avoid a negative aeration effect. The method validation was conducted with the customized test rig equipped with a transparent cylinder where the specific sliding intake valve was assembled. The proposed method also requires a lumped-parameter model of a twin-tube shock absorber, which allows to simulate boundary conditions in assessing particular reservoirs of a shock absorber, i.e., pressures and flow balance. The method is implemented as a calculation routine that converts CFD pressure regions into a gas concentration indicator (GCI) using the pressure-density characteristic of an oil-gas emulsion of a shock absorber. GCI is calculated based on the sum of particular 2D/3D grid elements. The method application is to minimize the risk of occurrence of negative aeration effects by avoiding expensive and time-consuming experimental tests. This method can also be used for in-production shock absorbers projects as a part of a continuous improvement cycle or in the case of inefficient shock absorbers claimed by a vehicle manufacturer. The application scope of the method can be extended for arbitrary twin-tube designs of shock absorbers in the automotive and railway industries.

10

Model of operational planning of freight transportation by tram as part of a green logistics system

Shramenko Natalya, Merkisz-Guranowska Agnieszka, Kiciński Marcin, Shramenko Vladyslav

Archives of Transport

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2022

|

Vol. 63, iss. 3

113--122

EN

The introduction of environmentally friendly technologies is becoming increasingly necessary to combat global warming and air pollution in cities. The concept of ecologistics is seen as an effective approach to the management of materials and related flows in order to reduce environmental and economic damage to the environment. The sustainable development of green supply chains is based on the use of environmentally friendly types of vehicles, reduction of energy and other resources consumption, optimization of transport and technological processes in delivery systems. As part of the development of green supply chain, it is proposed to transport goods by freight trams, which eliminates the need for heavy trucks in the city, improves traffic conditions and reduces the environmental impact of transport. The research was conducted for the city of Poznan. The distribution system of the city of Poznan operates in conditions of stochastic demand for deliveries from clients and the risk of lack of sufficient supplies in distribution centers. To take into account the specificity of the distribution system of cargo delivery in conditions of uncertainty and risk, a simulation model of the organization of the material flows within the transport system of the city of Poznan has been proposed. The result of simulation is the optimal assignment of clients to the distribution centers, as well as the value of total mileage with the load, which is a random variable. It is assumed that the random variable is distributed according to the normal distribution law. The results were calculated and compared for two variants, i.e. for constant demand and sufficient quantity of cargo in distribution centers, and for variable demand and uncertainty conditions, e.g. insufficient cargo quantity in distribution centers. The purpose of the paper is to develop a simulation model for planning supplies of small consignments of goods by trams implementing green logistics concept with variable demand for transportation. After a short introduction of the problem, the literature review related to the concept of green logistics and requirements of transport and distribution system are presented in section 2. In section 3, the research problem and research methodology are described. Section 4 provides the results of assignment of clients to distribution centers. The paper ends with concluding remarks.

11

Elektryczna lokomotywa akumulatorowa „Electra” ze zmiennym rozstawem kół

Lasek Paweł, Setlak Rafał, Zieleźny Wojciech, Kupczak Szymon

Napędy i Sterowanie

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2021

|

R. 23, nr 12

68--72

EN

The following paper presents a simulation model of a electric battery locomotive dedicated for mining. The mathematical models of a rail vehicle has been shown, with a analytical models describing an electric motor drive train, including battery system, traction and rolling losses. A set of key data for design and validation has been obtained in a simple drive cycle.

12

Experimental and numerical analysis of 3D printed cement mortar specimens using inkjet 3DP

Shakor Pshtiwan, Gowripalan Nadarajah, Rasouli Habib

Archives of Civil and Mechanical Engineering

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2021

|

Vol. 21, no. 2

287--302

EN

Investigations involving the experimental and numerical analysis of inkjet (powder-based) 3DP are relatively limited for cement mortar materials. This study, by using cement mortar specimens, aimed to determine the optimum strength of 3D printed structural members in all three planes by identifying the compressive strength of cubes, the modulus of elasticity and Poisson’s ratio. In addition, this study aimed to analyse and verify the numerical model for 3D printed cementitious mortar (CP) prisms and beams using an inkjet 3D printer by considering the mechanical behaviour of the printed prisms under compression. Robust and optimal mechanical properties of the 3D printed cementitious mortar obtained from laboratory testing were utilised in the simulation of structural components using ABAQUS software. As inputs for simulation, the strength properties of the printed objects in all three cartesian planes were obtained from test results. The obtained results showed that the printed cementitious materials have orthotropic properties and that the results of experiments were consistent with the analytical solutions and hypothesised model for the different geometric shapes. This finding is extremely valuable in determining the optimum features of 3D printed structures.

13

Application of a fuzzy controller in the process of automated polyethylene film thickness control

Jardzioch Andrzej, Marczak Wioletta

Applied Computer Science

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2021

|

Vol. 17, no 3

31--46

EN

The present article aims to describe the design of a fuzzy controller used for automated control of the thickness of the extruded polyethylene film effected by the adjustment of the actuator in the cooling ring. In order to determine whether the designed controller operates properly, a model extruder was created and a simulation study was carried out. The Simulink programming environment integrated with Matlab was used for the development of the fuzzy controller and the simulation. The conducted simulation study demonstrated that the implementation of the designed controller would enable the adjustment of thickness on the perimeter of the film tube and quick reaction to possible departure in the assumed film thickness in mass production.

14

Tilt test of a pallet load unit – simulation studies

Matyja Tomasz

Zeszyty Naukowe. Transport / Politechnika Śląska

|

2020

|

z. 107

107--117

EN

This paper presents a dynamic model of a palletised load unit during a static tilt test. The stability (also called rigidity) of a load unit was evaluated. The palletised load unit was built of packages forming layers and protected against disintegration by stretch film. The aim of this study was to compare the results of a static tilt test with a commonly used and recommended dynamic acceleration test.

15

Optimization of the duration of emergency vehicle movement to the place of fire

Pasnak Ivan, Renkas Artur

Transport Problems

|

2020

|

T. 15, z. 4, cz. 1

117--124

EN

The article is devoted to the issue of the negative effect of delays in the movement of special rescue vehicles on the effectiveness of their mission. The dependence of the area of fire on the delay of the arrival of firefighters using a fire-rescue vehicle is shown. The cascading graph of route options of special vehicle movement to the place of an emergency call is given. The algorithm of the optimal route choice of the special vehicle motion with given projected delays is offered. Based on the graph theory, probability theory, and the basic principles of traffic organization, the article proposes a new way to determine the optimal route.

16

Traffic simulation at unsignalized intersection in case of congestion on major street caused by an adjacent traffic sign

Gasz Krzysztof

Roads and Bridges - Drogi i Mosty

|

2020

|

Vol. 19, no. 3

211--224

EN

Unsignalized intersections belong to the most common ways of traffic management at intersections. The capacity of the minor entries depends on many factors. One of them is the traffic flow pattern on the major street. In the case of slow-moving queue of vehicles on the main street caused by a downstream traffic signal, the capacity of movements on the minor street joining the queue of vehicles on the main street is significantly reduced. The surveys of traffic parameters were performed in three Polish cities: Wroclaw, Opole, and Krakow. On the basis of these studies, a simulation model representing the traffic conditions at such an intersection was developed. The influence of pedestrian traffic and the number of storage spaces in the median on the possibility of vehicles from the minor entries joining the queue of vehicles on the main street was examined.

PL

Skrzyżowania bez sygnalizacji są jednym z najczęściej występujących sposobów organizacji ruchu na skrzyżowaniach. Przepustowość wlotów podporządkowanych uzależniona jest od wielu czynników. Jednym z nich jest sposób poruszania się pojazdów na jezdni głównej. W przypadku obecności poruszającej się powoli kolejki pojazdów spowodowanej przez oddziaływanie skrzyżowania z sygnalizacją, przepustowość relacji włączających się do kolejki z wlotów podporządkowanych jest znacznie ograniczona. Pomiary parametrów ruchu przeprowadzono w trzech miastach: Wrocławiu, Opolu i Krakowie. Na podstawie badań opracowano model symulacyjny odzwierciedlający warunki ruchu na skrzyżowaniu takiego typu. Przeanalizowano wpływ ruchu pieszego oraz pojemności powierzchni akumulacji w pasie rozdziału ulicy głównej na przepustowość pojazdów z wlotów podporządkowanych dołączających się do kolejki na jezdni głównej

17

Modele symulacyjne w doskonaleniu procesów logistycznych w systemach zarządzania kryzysowego

Zaskórski Piotr, Ogórek Mieczysław

Gospodarka Materiałowa i Logistyka

|

2019

|

nr 5

767--782, CD

PL

Współczesne organizacje funkcjonują w środowisku turbulentnym, które powoduje potrzebę wykorzystywania zaawansowanych technologii, a w tym m.in. systemów symulacyjnych, umożliwiających wcześniejszą ocenę sytuacji przy ustalonych ograniczeniach, jak również wariantowanie i wybór optymalnych rozwiązań. Bardzo duże znaczenie nabiera sprawność procesów logistycznych, które stają się główną determinantą ciągłości działania szczególnie w warunkach zaistnienia kryzysu i potrzeby utrzymania odpowiedniego poziomu bezpieczeństwa w dłuższym horyzoncie czasowym. Modele symulacyjne mogą więc sprzyjać doskonaleniu oraz usuwaniu prognozowanych luk w systemach logistycznych w różnych wymiarach zarządzania kryzysowego.

EN

Modern organizations operate in a turbulent environment that causes the need to use advanced technologies, including simulation systems, allowing for early assessment of the situation at set limits, as well as varianting and selection of optimal solutions. Very important is the efficiency of logistics processes, which become the main determinant of business continuity, especially in the conditions of crisis and the need to maintain an adequate level of security over a longer time horizon. Thus, simulation models can support the improvement and removal of forecast gaps in logistic systems in various dimensions of crisis management.

18

Warehouse location problem in supply chain designing: a simulation analysis

Szczepański Emilian, Jachimowski Roland, Izdebski Mariusz, Jacyna-Gołda Ilona

Archives of Transport

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2019

|

Vol. 50, iss. 2

101--110

EN

The facility location problem is a popular issue in the literature. The current development of world economies and globalization of the market requires continuous improvement of methods and research in this field. The location of the object determines the time of transport, affects the operational costs of the supply chain, and determines the possible amount of inventory or minimum inventory levels. These are critical issues from the point of view of designing an effective logistics system. The degree of complexity of current decision-making problems requires the construction of mathematical models and support for the decision-maker by optimization and simulation methods. A comprehensive and systemic approach to the problem allows the effective planning of supply chains. The purpose of this article was to study the sensitivity of the warehouse location problem in the supply chain. The solution was obtained based on the methodology developed under the SIMMAG3D project. The article presents the characteristics of the issue of the location of warehouse objects, the mathematical formulation of the solved problem of location and the method of its solution based on the heuristic algorithm using the modification of the Busacker-Gowen method. Then, a supply chain simulation model was developed in the FLEXSIM environment and scenario studies were performed for various input data and model parameters. The analysis and assessment of the solution based on parameters such as utilization of the potential of warehouse objects object were presented. Random change in demand described by Erlang distribution and normal distribution was considered. The analysis showed how the selection of a statistical distribution to describe the input data can affect the shape of the logistics system. The article ends with a summary of considerations and a plan for further research in the use of the simulation environment to support the decision-making process of the location of storage facilities and the functioning of supply chains.

19

Simulation model for maritime container terminal

Rusca F., Popa M., Rosca E., Rusca A.

Transport Problems

|

2018

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T. 13, z. 4

47--54

EN

For logistic chains that have a maritime component, the ports transition involves a set of specific operations inside maritime container terminals. This can be cargo handling operations from the terrestrial vehicle in the storage area of ports, from port storage area in the maritime ships, as well as storage operations in the port area and other container terminal activities. Taking into consideration the multi-flow interactions and the non-uniform arrival of vessels and in-land vehicles, discrete event simulation stands as a feasible technique for investigating berthing capacity during the initial planning stage of the terminal or for operative planning of logistic processes at the terminal. If the storage area is analysed as a queuing system, the quality serving attributes could be evaluate. When different distributions for arrival flows of the containers in the maritime container terminal are taken into consideration, the quality serving attributes are difficult to estimate. In our paper, a discrete simulation model is developed in ARENA software for case of a maritime container terminal. The estimation of the general measures of performance for the container port terminals through simulation could provide data for the implementation in the management plans by port administrations.

20

Prediction and validation for the aerodynamic noise of high-speed train power car

Jiang S., Yang S., Wu D., Wen B-Ch.

Transport Problems

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2018

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T. 13, z. 2

91--102

EN

The aerodynamic noise of high-speed train power car was investigated in this article. The full-scale power car was first modeled, and the external steady flow field was computed by a realizable k-ε turbulence model. The aerodynamic noise sources of the power car surface and the external transient flow field were then calculated by broadband noise source model and large eddy simulation (LES) model, respectively. The static pressures on the train surface were obtained from the results of the transient model. Considering the transient flow field, the far-field aerodynamic noise generated by the power car was finally derived from Lighthill-Curle theory. It was validated by means of on-line tests that have been performed along a real high-speed railway line. Through comparisons between simulations and measurements, it is shown that the simulation model gives reliable aerodynamic noise predictions. We foresee numerous applications for modeling and control of the aerodynamic noise in high-speed train.