Wyniki wyszukiwania - Biblioteka Nauki

1

About simulation modeling of HM-queueing network with unreliable systems

100%

Matalytski M. , Statkevich S.

Prace Naukowe Instytutu Matematyki i Informatyki Politechniki Częstochowskiej

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2012

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tom Vol. 11, nr 2

85-92

EN

The Markov network with unreliable queueing systems and incomes are considered. Analytical results on research of exponential networks in a case when incomes of transitions between network states depend on time are reduce. The algorithm of simulation modeling of HM-queueing networks based on the 0-moments. This method allows one to find incomes of networks when the service time of messages, serviceable work time of channels and restoration time of failure channels has any distribution. Results of simulation modeling are compared to analytical results. High accuracy of the developed algorithm is shown.

2

The life raft safety model sensitivity studies

100%

Smolarek L.

Journal of KONBiN

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2006

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tom No. 2

269--276

EN

Simulation modeling provides an effective and powerful approach for capturing and analyzing the life raft system [10]. The safety analysis can be based on computer generated data derived from simulation. This paper presents the sensitivity studies of the safety model that was developed to estimate the life raft safety parameters and to classify the hazard events importance.

3

Research on the risk classification of cruise ship fires based on an attention-BP neural network

80%

Xiong Z. , Xiang B. , Chen Y. , Chen B.

Polish Maritime Research

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2022

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tom nr 3

61--68

EN

Due to the relatively closed environment, complex internal structure, and difficult evacuation of personnel, it is more difficult to prevent ship fires than land fires. In this paper, taking the large cruise ship as the research object, the physical model of a cruise cabin fire is established through PyroSim software, and the safety indexes such as smoke temperature, CO concentration, and visibility are numerically simulated. An Attention-BP neural network model is designed for realizing the intelligent identification of a cabin fire and dividing the risk level, which integrates the diagnosis results of multiple neural network models through the self-Attention mechanism and adaptively distributes the weight of each BP neural network model. The proposed model can provide decision-making reference for subsequent fire-fighting measures and personnel evacuation. Experimental results show that the proposed Attention-BP neural network model can effectively realize the early warning of the fire risk level. Compared with other machine learning algorithms, it has the highest stability and accuracy and reduces the uncertainty of early cabin fire warning.

4

Controllling simulation experiment design for agent-based models using tree representation of parameter space

80%

Szufel P. , Kamiński B. , Wojewnik P.

Foundations of Computing and Decision Sciences

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2013

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tom Vol. 38, No. 4

277--298

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.

5

Observation of LEO objects using optical surveillance facilities: the geographic aspect

80%

Kozhukhov O. M. , Dementiev T. O. , Rischenko S. V. , Koshkin N. I. , Shakun L. S. , Strakhova S. L. , Piskun O. M. , Kozhukhov D. M. , Iluchok O. M. , Moskalenko S. S. , Korniyevskiy S. M.

Artificial Satellites : Journal of Planetary Geodesy

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2019

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tom Vol. 54, No. 4

113--128

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.

6

The use of simulation and genetic algorithm with different genetic operators to optimize manufacturing system

80%

Wiśniewski T. , Rymaszewski S.

Applied Computer Science

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2013

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tom Vol. 9, no 1

34--45

EN

The article depicts an evolutionary approach to simulation based optimization of a typical manufacturing system. Genetic algorithm with four different variants of genetic operators (crossover operator and type of selection) is compared to find the best optimization method. A comprehensive discussion of the genetic algorithm results obtained from the simulation model was also presented.

7

Characteristics and study of make-to-stock and make-to-availability production strategy using simulation modelling

80%

Ciechańska O. , Szwed C.

Management and Production Engineering Review

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2020

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tom Vol. 11, No. 4

68--80

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.

8

Simulation modeling of stationary systems reliability

80%

Wesołowski Z.

Studia Informatica : systems and information technology

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2012

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tom Vol. 1-2(16)

45--58

EN

A purpose of the article is describing the methodology of the simulation modeling of systems reliability. At the work is assumed that the process of the use of the studied system is stationary. An algorithm of the simulation applying the technique of discrete-event was presented. An example of using the proposed methodology to the reliability analysis of the air traffic control system was quoted.

9

Dispatching concrete trucks using simulation method

80%

Biruk S.

Budownictwo i Architektura

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2015

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tom Vol. 14, nr 2

s. 5--10

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.

10

Simulation modeLling for predicting hospital admissions and bed utilisation

80%

HAJŁASZ M. , MIELCZAREK B.

Operations Research and Decisions

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2020

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tom 30

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nr 3

5-19

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 simu-late 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%. 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 simu-late 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%.

11

Simulation modeling in GPSS for optimizing the traffic lights cycle of adjustable crossroads

80%

Kravchenya I. , Lebid I.

Journal of Sustainable Development of Transport and Logistics

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2020

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tom Vol. 5, No. 1

48--55

EN

The problem of traffic management, especially in big cities is particularly actual. Due to unavoidable motorization increase in number of vehicles has resulted in congestion, traffic jams, difficulty of the movement of pedestrians, increasing the number of accidents. Traffic jams are undesirable because of higher fuel consumption, increased pollution due to exhaust gases as well as noise, etc. The only way to avoid harmful consequences is to optimize the operation of the traffic lights cycle. The purpose of the work is creation the simulation model in GPSS for determining the optimal traffic lights cycle at adjustable crossroads when managing vehicle flows with specified intensities. The mathematical model of adjustable crossroads can be presented as a queuing system. Development of the simulation model includes several stages: programming in GPSS, verification and assessment of the adequacy. The algorithm for optimizing the traffic lights cycle and diagrams are used to find the optimal value of the cycle. The minimum intersection travel time (including time of queuing) is selected as the optimal criterion. The object of study is the traffic lights cycle regulation of the intersection Sovietskaya St. – Rogachevskaya St. – Telman St. in Gomel, Belarus. The existing traffic lights cycle regulation at the intersection Sovietskaya str. – Rogachevskaya str. – Telman str. has been studied. Simulation modeling of the intersection has been created in GPSS and traffic light cycle optimization algorithm has been developed. According to a worked out algorithm the traffic lights cycle at research intersection during saturation flux has been improved. Transport delays both at the existing and optimized crossings have been estimated. Optimization of the traffic lights cycle will increase the traffic capacity of the intersection, reduce the volume of toxic emissions and decrease the accident risk. The developed simulation model can be modified for other types of intersections and used as the basis for a decision support system based on low-level simulation.

12

A simulation study of Industry 4.0 factories based on the ontology on flexibility with using FlexSim® software

80%

Luściński S. , Ivanov V.

Management and Production Engineering Review

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2020

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tom Vol. 11, No. 3

74--83

EN

The main aim of the article is to develop a simulation model of flexible manufacturing system with applying the ontology on flexibility. Designing manufacturing systems matching both production and market requirements becomes more and more challenging due to the variability of demand for a large number of products made in many variants and short lead times. Manufacturing flexibility is widely recognised as a proven solution to achieve and maintain both the strategical and operational goals of the companies exposed to global competition. Generic simulation model of flexible manufacturing system was developed using FlexSim® 3D software, then the example data were used to demonstrate the developed model applicability. “The Ontology on Flexibility” was applied for evaluation of achieved flexibility of manufacturing system.

13

Simulation modeling for predicting hospital admissions and bed utilisation

80%

Hajłasz M. , Mielczarek B.

Operations Research and Decisions

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2020

|

tom Vol. 30, No. 3

5--19

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%.

14

Optimal gas transport management taking into account reliability factor

80%

Grudz V. , Grudz Y. , Zapukhliak V. , Chudyk I. , Poberezhny L. , Slobodyan N. , Bodnar V.

Management Systems in Production Engineering

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2020

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tom nr 3 (28)

202--208

EN

In the period of shortage of gas supply, special attention is given to reducing the supply of gas to its consumers, that is, their complete and uninterrupted gas supply. Increasing gas losses associated with technological transportation costs, in particular caused by gas flow instability and frequent changes in gas transmission network operating modes. Considering losses due to unreliability of gas pumping is one of the important tasks of gas supply optimization. The purpose of the study is to develop an optimization mathematical model that will simultaneously take into account the factors of reliability and minimum lossesIn the general case, the optimization calculations of the modes of operation of the main gas pipelines are intended to solve three main problems: determining the maximum productivity, calculating the optimal mode with a given productivity and choosing the optimal strategy, the development of the pipeline. On the basis of approaches of simulation modeling of complex systems, a multiparameter mathematical model of gas supply process optimization was developed. It is shown that a comparative analysis of the forecast and actual indicators of the operating modes of the plunger gas pumping unit shows their satisfactory convergence. The performance of the compressor operation period in the process of injection according to the forecast deviates from the actual value for the whole period of operation of the plunger gas pumping unit in 2016 by 2.98%. The optimization problem of gas pumping planning is considered, taking into account the expected losses, on the basis of which the transfer of the controlled system from the initial state to the final one is carried out by such a sequence of states that minimizes the total cost of the system evolution.

15

Simulation studies into quayside transport and storage yard operations in container terminals

80%

Deja M. , Dobrzyński M. , Siemiątkowski M. S. , Wiśniewska A.

Polish Maritime Research

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2017

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tom S 1

46--52

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

Characteristics and study of make-to-stock and make-to-availability production strategyusing simulation modelling

71%

Ciechańska O. , Szwed C. , Ciechańska O. , Szwed C.

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nr 4

17

On planning production and distribution with disrupted supply chains

70%

Szufel P.

Przegląd Statystyczny

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2022

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tom 69

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nr 2

20-36

EN

This paper presents a model for short-term time-horizon production and distribution planning of a manufacturing company located in the middle of a supply chain. The model focuses on an unbalanced market with broken supply chains. This reflects the state of the current post-COVID-19 economy, which is additionally struggling with even more uncertainty and disruptions due to the Russian aggression against Ukraine. The manufacturer, operating on the post-pandemic and post-war market, on the one hand observes a soaring demand for its products, and on the other faces uncertainty regarding the availability of components (parts) used in the manufacturing process. The goal of the company is to maximise profits despite the uncertain availability of intermediate products. In the short term, the company cannot simply raise prices, as it is bound by long-term contracts with its business partners. The company also has to maintain a good relationship with its customers, i.e. businesses further in the supply chain, by proportionally dividing its insufficient production and trying to match production planning with the observed demand. The post-COVID-19 production-planning problem has been addressed with a robust mixed integer optimisation model along with a dedicated heuristic, which makes it possible to find approximate solutions in a large-scale real-world setting.

18

Evaluation of ships turnaround time in port with approach channel

70%

Kuznetsov A. L. , Kirichenko A. V. , Semenov A. D.

Scientific Journal of Gdynia Maritime University

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2020

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tom nr 115

31--41

EN

The operation efficiency of a port with an approach channel to a great extent depends on decisions made by the port authority and harbor master over the channel scheduling. Currently there are no formal methods which allow to evaluate the influence of the channel schedule on the ship turnaround time, especially when the throughput capacity is restricted. The relevant system has a complex structure that rules out common mathematical methods. The paper studies some typical structures of these systems and offers an approach for developing adequate simulation models. These models enable the conduct of comparative studies of different variants of approach channel scheduling and serve as a toolkit to support the decision-making procedure for harbor master and port operators.

19

Energy and economic analysis of the use of photovoltaic in energy systems

70%

Szczerbowski R.

Computer Applications in Electrical Engineering

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2013

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tom Vol. 11

416--422

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.

20

Metody analizy statystycznej i geostatystycznej danych wykorzystywanych w modelowaniu złóż węglowodorowych

60%

Pańko A. , Łętkowski P.

Prace Instytutu Nafty i Gazu

|

2004

|

tom nr 130

533--539

PL

W pracy została zaprezentowana metodyka analizy danych geologicznych uwzględniająca ich wzajemne korelacje i przydatność do stworzenia geologicznego modelu złoża. Przedstawiono dwie grupy metod opisu struktury zbiorów danych: — statystyczną obejmującą tzw. miary położenia, rozrzutu, modele rozkładu danych (funkcja gęstości prawdopodobieństwa — histogram); — geostatystyczną obejmującą między innymi analizę wariograficzną (wariogram eksperymentalny, teoretyczny). Metody geostatystyczne dostarczają niezbędnych informacji do generowania przestrzennego opisu zmienności poszczególnych parametrów złożowych.

EN

The paper includes a theoretical description and practical examples of complite procedures to implement such a method consisting of: introductory statistical data analysis to determin general statistical features of the mesured data set; variografic analysis to determin spatial correlation of the data. The statistical methods includes: measure of location, dispersion, data model distribution (histogram — PDF). The geostatistical methods applied to data analysis (variogram experimental and theoretical) give information to generate spatial distribution main parameters of hydrocarbon reservoir.