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EN
Purpose: The purpose of this paper is to propose and evaluate two options for two-level transport solutions at the intersection of the bypass road and the Pidvolochyske Highway in Ternopil, Ukraine. The aim is to address the issues associated with the current road network passing through residential zones and present an optimal resolution for the intersection. Methodology: The methodology involves using the PTV Vissim software to conduct simulation modelling. The transport and operational indicators of the two options for two-level transport solutions, an elongated loop and two interconnected rings, are compared across different traffic intensities. Results: The results show that the transport solution with two roundabouts exhibits superior characteristics, particularly under high traffic flow conditions. The strengths and limitations of each solution are comprehensively delineated, encompassing factors like efficiency, cost-effectiveness, safety measures, and ecological impacts. Theoretical contribution: The paper contributes to advancing knowledge and practice in two-level transport solutions. It provides valuable insights for developing the transportation system in Ternopil and other post-conflict cities. The advantages and disadvantages of public-private partnerships (PPP) as a tool for attracting investments and innovations in transportation infrastructure are also discussed. Practical implications: The findings of this research can be used by professionals in transportation, urban planning, and ecology for infrastructure development. It also serves as a valuable resource for residents of Ternopil interested in fostering improvements to their city’s quality of life.
EN
In the work, studies were carried out on the use of vibration diagnostic methods for monitoring the state of induction motors with a squirrel-cage rotor, operated in electric drives of transport equipment. The most common and difficult-todiagnose damage to an induction motor is turn-to-turn short circuits in the stator winding, which require timely determination and establishment of the degree of damage to prevent an emergency shutdown of the equipment. The main purpose of the study is to establish the most effective areas of application of vibration diagnostic methods in determining the technical condition of the stator of induction motors under load. The experiments were carried out using simulation modeling for cases of turn-to-turn short circuits in one and two phases simultaneously, as well as with the influence of a low-quality supply voltage system on vibration parameters. The results of the work are relevant for further improvement of systems for diagnostic control of drives of transport equipment to increase the efficiency and reliability of their work.
EN
The impact of wind power plants on the environmental components is assessed taking into account a number of their parameters, in particular the technical characteristics of wind turbines, the characteristics of networks, engineering and other structures. To do this the life cycle of the wind power plants is described taking into account (by way of inventory) all the necessary materials and resources. Waste management scenarios have been developed, the use of which will make it possible to reduce the harmful impact on the environment. Based on the inventory and input data on the wind farm under study, a diagram is generated - a tree of life cycle processes of the wind power plant - to determine the potential environmental impacts. A list of impact categories that represent the load on the environment caused by the wind power plant is defined; also, the relative contribution of harmful factors is determined for each category, taking into account possible scenarios of waste management. Ecological profiles have been built for all potential impacts on the environment. After normalisation and determination of significance, individual estimates of all indicators and their distribution in three categories of lesions were obtained: human health, ecosystem quality and resources, as well as four stages of the wind farm life cycle: production, dismantling and disposal, operation, transportation and installation. The obtained profiles made it possible to determine individual indicators and eco-indicators, expressed in eco-points that characterise the wind farm under study.
EN
The paper studies two different types of container strategy: the traditional one, which involves container allocation into positions with a minimum stack height; and the “temperature” one, which considers the positions with a minimum “temperature” for the containers in the stack below. The “temperature” in this case means a metric which is connected to the storage (dwell) time of the containers. Particularly, this value can be represented by container selection probability or number of days stored in the container yard. Utilization of different metrics results in significantly different numbers of moves. Therefore, the authors compare two container stacking strategies: the traditional one and the temperature strategy with different metrics. It is stated that these strategies can be compared only by simulation modelling. The paper describes the main algorithms used to provide simulation modelling. The results of the research show that the temperature strategy with container dwell time as temperature metrics can save 6% of the total moves necessary to maintain the container flow.
EN
The article deals with the features and characteristics of intelligent systems for modelling business processes. Their classification was made and criteria for comparison were developed. According to the comparative analysis of existing expert systems for intelligent analysis, a reasonable choice of system for modelling business processes of a particular enterprise has been carried out. In general, it was found that the introduction of intelligent systems for modelling business processes of the enterprise and forecasting its activities for future allows management of the company to obtain relevant and necessary information for the adoption of effective management decisions and the development of a strategic plan.
6
Content available Robotic automation of inland container terminals
EN
The article presents the analysis of options for a transshipment terminal system with consideration of Russian transport system development. The aim is to determine the premises and possible problems, considering human absence, in the technological process at an inland container terminal. Statistical methods are used to analyze the market of robotic automation and the perspective for unmanned technology introduction. Simulation modeling of inland container terminal operation with various types of equipment, to study the applicability of robotic automation. The choice of modeling equipment results from the impossibility of completing an experiment on the real object, difficulties of analytical modeling (the system contains casual relations, nonlinear logic, stochastic variables), and the necessity to analyze the system’s time behavior. Consideration of robotic automation in a terminal warehouse complex is of particular importance due to technological progress followed by the freight terminal to be an area with highly organized technological processes and the need for highly paid specialists.
EN
Demographic research of the world population shows that societies are ageing. The ongoing changes in the population structure will require appropriate quantitative and qualitative adjustments in health services to meet the needs of society. Simulation methods turn out to be helpful in these kinds of analyses. In this paper, the authors present a case study on using discrete event simulation (DES) to support decision-making in the field of hospital bed management in the light of demographic changes. The case study was elaborated for one of the Polish district hospitals. A DES model was built to simulate admissions to two hospital wards: paediatric and geriatric. A series of experiments were carried out as based on real data extracted from the hospital database and forecasted demographic trends elaborated by the Central Statistical Office of Poland (CSO). The influence of demographic changes on hospital admissions in the chosen age-gender cohorts was explored, examining different variants of hospital bed availability. The results of the experiments show that demographic trends significantly influence healthcare admission and bed utilisation. The reduction in the number of admissions to the paediatric ward by about 6% results in a change in average bed utilisation from 57.90% to 54.06%. With about 12% more admissions to the geriatric ward, the change is from 68.88% to 75.59%.
EN
Make-To-Stock (MTS) and Make-To-Order (MTO) are the two traditional strategies in production management. In the case of the MTS there is a growing demand for a new approach, which is called Make-To-Availability (MTA) strategy. The paper characterizes and compares the MTS and MTA strategies. The comparative analysis based, among others, on computational experiments carried out in a computer program developed in Microsoft Visual Studio 2017 Environment was presented. The models have been prepared for both strategies with the same assumptions: external conditions (market demand) and internal conditions (structure of the production process). The investigation of how the strategies respond to various scenarios of demand intensity was done. The simulation models were prepared and validated for the case of the production line in one of the industrial automation company. The research shows that the use of the MTA strategy in the majority of cases gives much better results than the use of the MTS strategy due to the minimization of storage costs and the costs of non-fulfillment of the customers’ demand. The directions for further research were also presented.
EN
Transportation management is one of the areas that has strong impact on organization performance. If a company does not have expertise or resource, it would be better to outsource to logistics/transportation provider. The company can form contracts or hire trailers at spot rate. By forming a contract, specific number of trailers will be dedicated to the company and the cost per trip will be lower than the spot rate. However, there is a minimum number of trips requirement. If not properly managed, the company may end up paying more with the contract. The objective of this paper is to experiments with the simulation model to enable the manager to identify appropriate fleet size and negotiate for better contract condition, resulting in better on-time delivery and lower cost. The result shows that the company should increase the number of contracted trailers to match with the transportation needed and renegotiate the minimum number of trips per trailer per month. This will help the company significantly decrease late delivery and reduce costs. In addition, this study also use simulation model to plan for future contract negotiation when there are uncertainties in demand for transportation. Simulation model proves to be an important tool that enables one to gain better understanding of the contract situation and be able to manage the transportation contract that best suits the company’s objective.
PL
Zarządzanie transportem jest jednym z obszarów, który ma silny wpływ na wydajność organizacji. Jeśli firma nie ma specjalistycznej wiedzy ani zasobów, lepiej zlecić usługi logistyczne / transportowe. Firma może zawierać umowy lub wynajmować przyczepy według stawki spot. Poprzez zawarcie umowy konkretna liczba naczep zostanie poświęcona firmie, a koszt przejazdu będzie niższy niż stawka kasowa. Istnieje jednak minimalna liczba podróży. W przypadku niewłaściwego zarządzania firma może ostatecznie zapłacić więcej z tytułu umowy. Celem tego artykułu jest eksperymentowanie z modelem symulacyjnym, aby umożliwić menedżerowi zidentyfikowanie odpowiedniej wielkości floty i negocjowanie lepszych warunków umowy, co skutkuje lepszą terminowością dostawy i niższymi kosztami. Wynik pokazuje, że firma powinna zwiększyć liczbę zakontraktowanych przyczep, aby dopasować je do potrzebnego transportu i renegocjować minimalną liczbę przejazdów na przyczepę miesięcznie. Pomoże to firmie znacznie ograniczyć opóźnione dostawy i obniżyć koszty. Ponadto w tym badaniu wykorzystano również model symulacyjny do planowania przyszłych negocjacji umów, gdy istnieje niepewność co do popytu na transport. Model symulacyjny okazuje się ważnym narzędziem, które pozwala lepiej zrozumieć sytuację kontraktową i być w stanie zarządzać umową transportową, która najlepiej odpowiada celowi firmy.
EN
Simulation modelling of the observability of low Earth orbit (LEO) objects was performed using optical surveillance facilities depending on their geographic location and time of year. Orbital data for LEO objects from the open-access catalogue of the near-Earth space objects of the US Combined Space Operations Center (CSpOC) were taken as the initial data for the simulation. The simulation results revealed a complex relationship between the pattern of observability of a LEO object, its orbital parameters and location of the optical surveillance facility, in particular, for Sun-synchronous orbits (SSO) and observing facilities located near the equator. We also discuss variations in the frequency of passes of LEO objects into the field of view (FOV) and in the duration of their observation while passing through the FOV for optical surveillance facilities at three alternative locations. The obtained results and modelling techniques can be further used in the location planning of new optical observing facilities.
11
EN
Abstract This article presents investigations performed on a 25 kV AC system with a Scott transformer simulation model. The model includes an energy quality parameter calculation algorithm with consideration to the train timetable. The simulation results enable an analysis of the energy quality parameters at the point of connection of the traction substation to the supplying grid. The presented tool enables the simultaneous calculation of voltage unbalance and harmonic content. The article presents the results of the energy quality analysis at the substation connection point for the specific location. The simulation results of the energy quality parameters are appraised on the basis of standard EN 50160:2010. The tool may prove helpful in the process of designing electrification systems, especially in the choice of traction transformer and power electronics device mitigating an imbalance and harmonic impact.
PL
Artykuł przedstawia badania przeprowadzone z wykorzystaniem modelu symulacyjnego systemu zasilania prądu przemiennego 25 kV 50 Hz z transformatorem Scotta, uwzględniającym wszystkie czynniki jakości energii elektrycznej przy uwzględnieniu rozkładu jazdy pociągów. Wyniki badań pozwalają na kompleksową analizę parametrów jakości energii w punkcie przyłączenia podstacji trakcyjnej do systemu elektroenergetycznego przy uwzględnieniu rozkładu jazdy pociągów oraz rodzaju taboru. W porównaniu z innymi opublikowanymi pracami przedstawione narzędzie pozwala na określenie zarówno asymetrii napięciowej jak i harmonicznych napięcia w punkcie przyłączenia podstacji trakcyjnej. Narzędzie może być przydatne procesie projektowania układu zasilania, w szczególności doboru urządzenia symetryzującego na podstacji trakcyjnej dla danej lokalizacji tak, aby uzyskać spełnienie wymagań normatywnych.
EN
This paper aims to develop an approach to identify optimal fleet size under uncertainty and to identify important factors affecting transportation performance. The methodologies used in this paper are two folded. The first methodology is to develop a simulation model that allows manager to evaluate the impact of having different number of trailers on delivery and cost in order to identify the optimal fleet size. The second methodology is to use a Design of experiment (DOE) together with the simulation model to identify important factors that affect transportation performances. The result shows that the company should hire 16 trailers, which will reduce the delivery delay from 14% to 0.02%. Furthermore, it is found that variation in demand has a strong impact on late delivery and cost. There is also an interaction between demand variation and transportation time variation.
PL
Niniejszy dokument ma na celu opracowanie podejścia do określania optymalnej wielkości floty w warunkach niepewności oraz określenie ważnych czynników wpływających na wydajność transportu. Metodologie stosowane w tym artykule są złożone. Pierwszą metodologią jest opracowanie modelu symulacyjnego, który umożliwi menedżerowi ocenę wpływu posiadania różnych przyczep i kosztów w celu określenia optymalnego rozmiaru floty. Drugą metodologią jest wykorzystanie projektu eksperymentu (DOE) wraz z modelem symulacyjnym w celu zidentyfikowania ważnych czynników wpływających na wydajność transportu. Wynik pokazuje, że firma powinna wynająć 16 przyczep, co zmniejszy opóźnienie dostawy z 14% do 0.02%. Ponadto stwierdzono, że zróżnicowanie popytu ma duży wpływ na opóźnienia w dostawie i koszty. Istnieje również interakcja między zmiennością popytu a zmiennością czasu transportu.
13
Content available Micro- vs. Macro scope simulation in BPM modelling
EN
The business structure and process development in many modern companies is assisted by architectures, frameworks, and a new generation of computer systems with a broad representation of methods and tools of design and modelling, i.e. object-oriented, event-oriented, activity-oriented, process-oriented, agent-oriented, communication-oriented, behaviour-oriented, etc. are recommended. The aim of this paper is to compare micro- vs. macro scope modelling and to investigate the relevance of micro- and/or macro simulation in the context of business process management (BPM) modelling for organizational design/redesign. The BPM modelling features and some specific issues of simulation modelling are discussed. Combined with BPM modelling methodologies, these issues are used to drive a concept for development of an integrated methodology for BPM models’ building and simulation approach in organizational BPM design/redesign projects.
14
Content available remote Symulacyjne badania bezpieczeństwa pracowników magazynowych
PL
W artykule przedstawiono pewne podejście do badania bezpieczeństwa pracowników obiektów magazynowych. Dokonano identyfikacji i analizy najczęściej spotykanych w systemach magazynowych wypadków z udziałem ludzi. Na jej podstawie ustalono, że w niniejszym artykule główna uwaga zwrócona zostanie na wypadki i kolizje związane z użytkowaniem wózków widłowych. Dodatkowo założono, że eksperymenty symulacyjne, badanie przebiegu i zmian procesów w wybranych układach transportu wewnętrznego i magazynowania pozwolą na identyfikację miejsc występowania sytuacji niebezpiecznych dla pracowników magazynowych oraz liczby takich sytuacji. W tym celu opracowano modele symulacyjne różnych wariantów organizacyjnych układów magazynowych i przeprowadzono szereg symulacji (z wykorzystaniem narzędzia FlexSim). Badania symulacyjne pozwoliły na oszacowanie liczby sytuacji potencjalnie niebezpiecznych dla operatorów wózków widłowych (sytuacji kolizyjnych), którą następnie wykorzystano do oceny bezpieczeństwa pracowników magazynowych.
EN
The paper presents some approach to analyse safety of the warehouse employees. The identification and analysis of the most common accidents (involving persons) in storage systems was made. It was the basis for the fact that in this paper will focus on accidents and collisions of forklifts. In addition, it was assumed that simulation experiments of internal transport process in selected internal transport and storage systems will allow identification hazardous locations for warehouse workers and the number of such situations. Besides, simulation models of various variants of warehouse systems were developed and were performed some simulations (using the FlexSim tool). Simulation experiments have allowed us to estimate the number of potentially dangerous situations for forklift operators (collision situations). Number of such situations was used to evaluate the safety of warehouse workers.
EN
The focus of the paper is in quayside transport and storage yard operations in container terminals. Relevant algorithms have been applied and a simulation model adopted. Evaluative criteria chosen for that model were: the total time of ship unloading and the truck utilization level. Recommendations for unloading in berth and yard areas were analysed in three different case studies. Results of simulations and deterministic model based analyses are included.
16
Content available Logistics management as a system constraint
EN
This paper presents a comparative simulation model of several logistic systems and their impact on operational performance. It stresses the importance of logistic processes and their management in the context of lean production and the theory of constraints. The main goal of our experimental study is to prove how significantly supporting logistic processes can influence production process performance in situations where logistic management represents a system constraint. More specifically, our study considers the capacity of handling units, and their impact on material flow continuity and efficiency. The experimental model is based on real data that was acquired by the authors over the last several years during their research and practical experience. Our results are presented in the form of software statistics that were provided after the experiment and compared with the set hypotheses. The experimental study has shown that a managerial decision to increase the capacity of handling units does not always result in the expected behaviour pattern.
PL
Niniejszy artykuł prezentuje porównawczy model symulacji kilku systemów logistycznych i ich wpływ na wydajność operacyjną. Podkreśla znaczenie procesów logistycznych i zarządzania nimi w kontekście szczupłej produkcji i teorii ograniczeń. Głównym celem naszych badań eksperymentalnych jest udowodnienie, jak znaczne wspieranie procesów logistycznych może wpłynąć na wydajność procesu produkcyjnego w sytuacjach, w których zarządzanie logistyczne stanowi ograniczenie systemu. Ujmując problem bardziej szczegółowo, nasze badanie uwzględnia pojemność jednostek manipulacyjnych oraz ich wpływ na ciągłość przepływu materiału i wydajność. Eksperymentalny model oparty jest na rzeczywistych danych, które zostały zebrane przez autorów w ciągu ostatnich kilku lat w trakcie ich badań i praktycznych doświadczeń. Wyniki przedstawione zostały w formie statystyk oprogramowania dostarczonych po eksperymencie i porównanych z założonymi hipotezami. Badanie eksperymentalne wykazało, że decyzja menedżerska, dotycząca zwiększenia pojemności jednostek manipulacyjnych, nie zawsze prowadzi do oczekiwanego wzorca zachowań.
Logistyka
|
2015
|
nr 3
423--431, CD 1
PL
Właściciele wytwórni betonu towarowego dążą do maksymalizacji zysku, zwiększenia liczby zrealizowanych zamówień i racjonalnego wykorzystania potencjału produkcyjnego. Planowane terminy dostaw mieszanki betonowej muszą być dostosowane do harmonogramu prac betonowych na budowach. Zadaniem dyspozytora jest ustalenia harmonogramu załadunku betonowozów i kolejności realizacji dostaw na budowy. Wybór strategii rozdziału środków transportowych wpływa na koszty funkcjonowania betonowni oraz czas i koszty trwania robót budowlanych. W artykule scharakteryzowano problem zintegrowanego harmonogramowania produkcji mieszanki betonowej i marszrutyzacji betonowozów oraz opracowano model symulacyjny, który umożliwia ocenę strategii rozdziału betonowozów. Model może stać się skutecznym narzędziem wspomagającym pracę dyspozytora. Głównym kryterium oceny strategii jest czas realizacji wszystkich zleceń i ciągłość prowadzenia robót betonowych na budowach. Elastyczne dostosowywanie się do wymagań zmawiającego, w zakresie składu i jakości mieszanki betonowej oraz terminowości dostaw, może stać się jednym z kluczowych czynników sukcesu producenta betonu towarowego na rynku.
EN
Ready mix concrete plant owners are focused on maximizing profit. This can be achieved by increasing the number of served orders thanks to optimal use of resources. The mix delivery schedules must stay in accordance with the schedules of construction work on the building sites. Therefore, the dispatcher’s decisions on production, loading and delivery are of key importance. The strategy of using the limited number of concrete trucks affects the plant’s operating cost and cost of construction works. The paper describes the problem of integrated production scheduling and truck dispatching and presents a simulation model that facilitates assessment of dispatching strategy. The main criterion of strategy assessment is the total time of serving all orders and continuity of works on construction sites. The model can be a useful tool supporting the dispatcher’s decisions. The ready mix concrete plant flexibility in responding to the client’s needs in terms of both the product qualities and the delivery schedules may be a key success factor in this demanding market.
18
Content available Dispatching concrete trucks using simulation method
EN
Ready mixed concrete (RMC) is the primary material required for buildings and public infrastructure work. RMC is produced to meet customer’s demands and its deliveries must conform to construction site and technological operating constraints – the material cannot be prepared in advance and stored. Concrete production scheduling and truck dispatching is mainly handled manually by experienced RMC batching plants staff. The paper presents simulation model which can be used to asses alternative strategies for truck allocation and production planning in stochastic environment. The models’ operation is illustrated by a notional case – the model prompted solutions of improved transhipment efficiency and reduced plant operating cost under assumed operating constraints.
EN
An important aspect of the simulation modelling process is sensitivity analysis. In this process, agent-based simulations often require analysis of structurally different parameter specifications – the parameters can be represented as objects and the object-oriented simulation configuration leads to nesting of simulation parameters. The nested parameters are naturally represented as a tree rather than a flat structure. The standard tools supporting multi-agent simulations only allow only the representation of the parameter space as a Cartesian product of possible parameter values. Consequently, their application for the required tree representation is limited. In this paper an approach to tree parameter space representation is introduced with an XML-based language. Furthermore, we propose a set of tools that allows one to manage parameterization of the simulation experiment independently of the simulation model.
EN
Energy policy of Poland in a balanced way has to provide security of energy supply, increase the use of its own resources and promote the sustainable development of different electricity generation technologies. The established aims of climate and energy policy will be difficult to achieve without efficient technologies based on distributed generation. In this context, the importance of the development and use of photovoltaic systems is growing. Photovoltaics is one of the most promising technologies and the possibilities of its use in various scale energy systems make it an effective and safe source of energy and an important part of a stable and independent energy mix in the future.
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