Wyniki wyszukiwania - BazTech

1

Management system structure vs. Behavior - a supply chain simulation analysis

Pietroń Roman

Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

|

2023

|

z. 169

575--597

EN

Purpose: The purpose of this article is to present a research report on a system dynamics simulation modeling and experimenting of bullwhip effect (BWE) to examine effectiveness of some selected inventory control policies with down- and upstream information flow in a Beer Distribution Game (BDG) of a supply chain structure. Design/methodology/approach: The impact of systems’ structures and decision making policies in supply chains or logistics systems are measured and analyzed by an application of systems thinking paradigms and approaches. Particularly, the continuous simulation modeling approach with systems thinking Iceberg model metaphor, allowing to focus on strategic aspects of management with some recommendation to design better structures and decision making policies are taken. For the bullwhip effect analysis of a supply chain example (based on BDG model), a System Dynamics (SD) continuous simulation modeling method with some proposals in order to analyze feedback loop dominance are undertaken to explain supply chain behaviors and to make some sensitivity analysis for decision making (inventory control) policies. Findings: The research findings outline the impact of cause - effect relations, feedback loops polarities, and decision making policies to particular behaviors of the BDG supply chain. Research limitations/implications: Because of complexity of heuristic methods for feedback loop dominance analysis only simple approach was applied (LPD), and some selected scenario for simulation experiments were undertaken resulting in limited conclusions. Practical implications: The conclusions of the research draw some practical recommendations for a design of information sharing system and an effectiveness of some inventory control policies to be applied in supply chains. Social implications: One of the systems thinking elements in practical management is an influence to mental models of managers and decision makers. Managers in supply chain systems particularly need some recommendations to avoid bullwhip effect negative impacts. Additionally, managers and also scholars still call for more research to investigate the design and decision making in supply chains, therefore systems thinking simulation research can bridge the gap between traditional operations research and management with other approaches to provide insight into supply-chain dynamics and deliver impactful suggestions to managers. Originality/value: The paper gives a concept of supply chain dynamic analysis by an application of Iceberg model systems thinking metaphor, feedback loop dominance analysis, and a measurement of some selected inventory control policies effectiveness.

2

Preventing the development of emergency modes of interlocked electric drives of a rolling mill under the impact loads

Druzhinin Valeriy, Sivyakova Galina, Kalinin Alexey, Tytiuk Valerii, Nikolenko Anatolii, Kuznetsov Vitaliy Vadimovich, Kuzmenko Mykhailo

Diagnostyka

|

2023

|

Vol. 24, No. 1

art. no. 2023105

EN

In recent years, due to the tightening of competition in the global market of steel producers, the requirements for the quality of hot-rolled steel have increased. The finishing group of the rolling mill is characterized by a complex structure of mechanical and electrical parts. The operation of electric drive systems of such units is characterized by the interrelation of electromagnetic processes, mechanical phenomena and technological factors. As experimental studies have shown, the quality of the supply voltage is inextricably linked with the impact nature of the loads in the rolling stands of the roughing and finishing groups of the hot rolling mill. A decrease in the supply voltage may be accompanied by the development of emergency modes of synchronous electric drives, leading to a decrease in the quality of the finished product.The paper developed a mathematical model of the power supply system of the rolling mill JSC "ArcelorMittal Temirtau". It is shown that this can lead to loss of synchronism of the synchronous motor. Such a voltage drop has a significant impact on the operation of DC electric drives of the finishing group. Various strategies are proposed to counter the development of emergency situations.

3

Proactive-reactive repetitive project scheduling method - the concept of risk consideration at the project planning and execution stage

Jaśkowski Piotr, Biruk Sławomir, Krzemiński Michał

Archives of Civil Engineering

|

2023

|

Vol. 69, nr 4

89--104

EN

The construction contractor is concerned with reducing the cost of the project, including reducing unnecessary downtime. This is achieved when resources are fully utilized; this means the crews work continuously moving without interruption from one location to the other. However, any disturbance in the optimally scheduled workflow caused by random events is likely to result in delays, interruptions in the crews work, and productivity losses. There is therefore a need for scheduling methods that allow plans to be more resilient to disruptions and ensure a reduction in downtime and implementation costs. The authors put forward a proactive-reactive approach to the schedule risk management. Proposed method makes it possible to protect schedule deadlines from the impact of risk factors by allocating time buffers (proactive approach). It also takes into account the measures that managers take during execution in response to delays that occur, such as changing construction methods, employing extra resources, or working overtime (reactive approach). It combines both ideas and is based on project simulation technique. The merits of the proposed approach are illustrated by a case of a repetitive project to erect a number of buildings. The presented example proves that the proposed method enables the planner to estimate the scale of delays of processes’ start and consider the impact of measures to reduce duration of processes in particular locations taken in reaction to delays. Thus, it is possible to determine the optimal schedule, at which the costs of losses associated with delays and downtime are minimal.

PL

Najlepsze rezultaty realizacji przedsięwzięć budowlanych są osiągane wówczas, gdy brygady pracują bez przerw i po zakończeniu procesu na jednej części obiektu (działce roboczej) mogą rozpocząć pracę na działce kolejnej, na której zakończono wykonanie procesów poprzedzających. Dzięki ciągłości pracy brygad i powtarzalności realizacji tych samych zadań na poszczególnych działkach roboczych może wystąpić efekt uczenia się i redukcji czasu wykonania zadań. Zakłócenia w realizacji robót, na skutek oddziaływania czynników ryzyka o charakterze losowym, mogą prowadzić do opóźnień w wykonaniu procesów poprzedzających i w efekcie do przestojów w pracy brygad oraz wydłużenia czasu realizacji całego przedsięwzięcia. W związku z tym istotne jest rozwijanie metod harmonogramowania uwzględniających dynamikę rzeczywistego przebiegu wykonania procesów w zmiennych warunkach realizacyjnych. Redukcja odchyleń terminów zaplanowanych od rzeczywistych umożliwia zmniejszenie kosztów związanych z ich przekroczeniem, m.in. zamrożenia środków obrotowych w zapasach, przestojów w pracy brygad roboczych, kar umownych za niedotrzymanie terminów kontraktowych itp. Zdeterminowane terminy realizacji procesów w harmonogramie pozwalają na tworzenie planów produkcji pomocniczej, optymalizację zaopatrzenia budowy w materiały i sprzęt, pozyskiwanie zasobów ludzkich i zawieranie kontraktów z podwykonawcami. Ryzyko wystąpienia opóźnień może być uwzględnione już na etapie harmonogramowania poprzez określenie wielkości buforów czasu i ich alokację w harmonogramie. Takie podejście jest określane mianem harmonogramowania proaktywnego. Nawet mimo uodpornienia harmonogramu przy zastosowaniu metod proaktywnych, w trakcie realizacji mogą pojawić się nieprzewidziane zdarzenia, które powodują, że ochrona taka jest niewystarczająca i rozpoczęcie kolejnych zadań w zaplanowanych terminach jest niemożliwe ze względu na opóźnienia procesów poprzedzających lub niezwolnienie niezbędnych zasobów. Zachodzi wówczas konieczność reakcji - podjęcia działań redukujących odchylenia od planu lub aktualizacji planu. W reakcji na zakłócenia są podejmowane działania zmierzające do skrócenia czasu procesów jeszcze niewykonanych (zmiana wariantu technologicznego wykonania procesu, zatrudnienie dodatkowych zasobów, praca w nadgodzinach lub wydłużony tydzień pracy). W artykule zaproponowano podejście do uwzględnienia ryzyka o charakterze proaktywno-reaktywnym, wykorzystujące metodę symulacji cyfrowej w celu oszacowania wielkości opóźnień terminów rozpoczynania kolejnych procesów z uwzględnieniem reaktywnych działań redukujących czas ich wykonania na działkach roboczych, podejmowanych już w fazie realizacji. W proponowanej metodzie proaktywno-reaktywnego harmonogramowania przedsięwzięć powtarzalnych zakłada się, że czasy realizacji procesów są zmiennymi losowymi o znanej funkcji gęstości i parametrach rozkładu.

4

Simulation modeling for evaluation of efficiency of observed ship coordinates

Vorokhobin I., Burmaka I., Fusar I., Burmaka O.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

|

2022

|

Vol. 16 No. 1

137--141

EN

Simulation computer modeling was used to evaluate the efficiency of the vessel’s observed coordinates using the mixed laws of distribution errors of the first and second type for lines of position (LOP). Simulation modeling showed good convergence of evaluation of efficiency calculated by analytical expressions and obtained by simulation. A graphical depiction of the observed points’ deviation relative to the mathematical expectation in the case of distribution of LOP errors of both types according to mixed laws is obtained by the method of least squares and the method of maximum likelihood estimation.

5

Comparison of the results of simulation modeling of an asynchronous electric motor with the calculated electrodynamic and energy characteristics

Gubarevych Oleg, Golubieva Svitlana, Melkonova Inna

Przegląd Elektrotechniczny

|

2022

|

R. 98, nr 10

61--66

EN

The paper presents the results of a comparison of the electrodynamic and energy characteristics and parameters of an asynchronous motor, obtained by simulation and calculated by the classical method. The mathematical model in the MATLab software environment is used for research. The research results are relevant when choosing and using the proposed simulation model of three-phase squirrel-cage asynchronous motors for further research, including the effect of various engine defects on its performance.

XX

W artykule przedstawiono wyniki porównania charakterystyk i parametrów elektrodynamicznych i energetycznych silnika asynchronicznego, uzyskanych metodą symulacji i obliczonych metodą klasyczną. Do badań wykorzystano model matematyczny wykonany w środowisku oprogramowania MATLab. Wyniki prac mają istotne znaczenie dla wyboru i wykorzystania zaproponowanego modelu symulacyjnego asynchronicznego silnika elektrycznego z wirnikiem klatkowym do dalszych badań, w tym wpływu różnego rodzaju uszkodzeń silnika na jego pracę.

6

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

Xiong Zhenghua, Xiang Bo, Chen Ye, Chen Bin

Polish Maritime Research

|

2022

|

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.

7

Elaborationand research of a model of optimal production and development of industrial systems taking into accountthe use of the external resources

Hryshyn Dmytro, Borovska Taisa, Kalizhanova Aliya

Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska

|

2022

|

T. 12, nr 4

60--66

EN

The problem of optimization of investment projects related to the development of modern production systems is considered. The tasks of managing of operation and development of production systems considering external resources – the synthesis and analysis of optimal credit strategies – are posed and solved. An analysis of analogs – solutions of the variational problem of optimal development, the disadvantage of which is the difficulty of obtaining information about the state of production and the external environment, was carried out. The new solution is based on the resource approach, when external resources are taken into account in the cost of production resources. A generalized model of optimal development is used, in which the planned period of the investment project is divided into intervals. At the beginning of each interval, the optimal development strategy is adjusted taking into account the clarification of information about the future state of the active environment: actions of competitors, consumers, world markets. To determine the optimal amount and optimal distribution of credits between subsystems, the maxima of the criterion – the parameterized function of the system's efficiency – are determined at each interval. A new model has been developed based on the model of optimal development, which takes into account the use of external resources, such as loans. The method of including an external resource in the development function and the production function is considered. Examples of modeling are given.

PL

Rozpatrywany jest problem optymalizacji przedsięwzięć inwestycyjnych związanych z rozwojem nowoczesnych systemów produkcyjnych. Postawiono i rozwiązano zadania zarządzania funkcjonowaniem i rozwojem systemów produkcyjnych z uwzględnieniem zasobów zewnętrznych – synteza i analiza optymalnych strategii kredytowych. Przeprowadzono analizę analogów – rozwiązań wariacyjnego problemu optymalnego rozwoju, którego wadą jest trudność uzyskania informacji o stanie produkcji i otoczeniu zewnętrznym. Nowe rozwiązanie oparte jest na podejściu zasobowym, kiedy to zasoby zewnętrzne są uwzględniane w kosztach zasobów produkcyjnych. Wykorzystano uogólniony model optymalnego rozwoju, w którym planowany okres realizacji projektu inwestycyjnego podzielono na przedziały. Na początku każdego interwału optymalna strategia rozwoju jest korygowana z uwzględnieniem doprecyzowania informacji o przyszłym stanie otoczenia aktywnego: działań konkurentów, konsumentów, rynków światowych. W celu określenia optymalnej ilości i optymalnej dystrybucji kredytów pomiędzy podsystemami, w każdym interwale wyznaczane są maksima kryterium – sparametryzowanej funkcji efektywności systemu. Na podstawie modelu optymalnego rozwoju opracowano nowy model, który uwzględnia wykorzystanie zasobów zewnętrznych, takich jak kredyty. Rozpatrzono metodę uwzględniania zasobu zewnętrznego w funkcji rozwoju i funkcji produkcji. Podano przykłady modelowania.

8

Evaluation of ships turnaround time in port with approach channel

Kuznetsov Alexander L., Kirichenko Alexander V., Semenov Anton D.

Scientific Journal of Gdynia Maritime University

|

2020

|

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.

9

Integrated Approaches to Determination of CO2 Concentration and Air Rate Exchange in Educational Institution

Deshko Valerii, Bilous Inna, Vynogradov-Saltykov Volodimer, Shovkaliuk Maryna, Hetmanchuk Hanna

Rocznik Ochrona Środowiska

|

2020

|

Tom 22, cz. 1

82--104

EN

Many old public buildings in Central and Eastern Europe are characterized by low energy efficiency and often lack of mechanical ventilation. The general trends are aimed to improve the energy efficiency of the building sector and to provide comfort conditions. The indoor air quality can be determined based on the CO2 concentrations. In the article, a complex approach to the definition and analysis of data on the indoor CO2 concentration and the air exchange rate in educational institutions at natural air exchange and in the absence of mechanical air circulation was implemented. Educational institutions in Kyiv have been considered. The study of the CO2 concentration of indoor and outdoor air of three typical schools of mass development in the 80 s, as well as the training building of Igor Sikorsky KPI, was carried out. Experimental determination of the background CO2 concentration during the day next to the considered objects showed that the background concentration of CO2 is in the range of 400-420 ppm. Measurements of the CO2 concentration distribution were carried out after classes throughout the classroom area, according to which the difference between the values at the level of the working area was 30...180 ppm. It was found that the concentration of CO2 varies during classes between 700-1100 ppm. During the break, the CO2 concentration decreases to 500-1000 ppm, depending on the type of ventilation. Experimental data on the dynamics of changes in the indoor CO2 concentration are used to determine the air exchange rate based on balances of air flows and CO2. It is shown that the number of present persons influences the indoor CO2 concentration more significantly than the air exchange rate. On the example of an experimental study of the CO2 concentration in the classrooms for high school students it was found that the air exchange rate during the classes is in the range of 0.4...0.75 h-1. During breaks the air exchange rate increases to 2.9-3.5 h-1. For the range considered, the weighted average air exchange rate is 0.8 h-1, and even with forced airing, the air exchange rate is insufficient to ensure acceptable CO2 concentration. For the training building of Igor Sikorsky KPI a field experiment was carried out to determine the dynamics of changes in CO2 concentration in time and on the basis of it the air exchange rates for representative classrooms were determined. The concentration of CO2 ranged from 500 to 2000 ppm and increases by 350-850 ppm depending on the use and location of classrooms. Based on experimental data, the air exchange rate for the training building of the education institution is in the range of 0.35-0.7 h-1. During the periods of airing the air exchange may increase by 0.45 h-1, but this does not allow reaching the standard value. When analyzing the obtained results, simulation models of natural air exchange of the examined classrooms were used on the basis of the improved ASHRAE method. The natural air exchange rate based on simulations is in the -0.8…0.5 h-1 range. Negative values are explained by exfiltration, which is typical for the upper floors. Not only the comfort and condition of the building envelope, but also the total energy consumption of the building depend on the actual level of air exchange rate. In the total energy balance the ventilation component is 30-60%. Further use of the obtained results can be connected with monitoring of the actual level of air exchange rate and its consideration during complex modernization or implementation of the ventilation systems with heat recovery in the premises of educational institutions.

10

Optimal gas transport management taking into account reliability factor

Grudz Volodymyr, Grudz Yaroslav, Zapukhliak Vasyl, Chudyk Ihor, Poberezhny Lubomyr, Slobodyan Nazar, Bodnar Vitaliy

Management Systems in Production Engineering

|

2020

|

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.

11

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

Kravchenya Irina, Lebid Iryna

Journal of Sustainable Development of Transport and Logistics

|

2020

|

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

The use of simulation modeling in the design of elements of annular preventers

Dzhus Andriy, Romanyshyn Liubomyr, Mykhailiuk Vasyl, Mosora Yurii

New Trends in Production Engineering

|

2019

|

Vol. 2, Iss. 1

295--303

EN

One of the main elements of control over wells in the process of their construction is the blowout equipment, which includes annular preventers. This also applies to wells that provide degassing of coal veins to reduce their gas dynamic activity. Modern technology of work requires expansion of the functionality of the sealing unit of the annular preventers with the simultaneous provision of its operational characteristics. Determining the necessary durability of seals for different operating modes is the study of their stress-strain state. The paper deals with the possibility of using simulation modeling in the annular preventers design situations and within the study of the armature geometry influence of the sealant fittings on its stress-strain state. The method of determining the material constants to realize the Mooney-Rivlin model has been proposed. The behavior of low-density rubber in software product has been described by the finite element method. The aggregation error of experimental and theoretical studies is 5%. Therefore, the preconditions and the possibility of using simulation modeling in the design of annular preventers devices with increased operational characteristics have been created and confirmed.

13

Simulation Model of GPRS Channels Operation as a Part of the Railway Traffic Coordination System

Akhmetov Bakhytzhan, Lakhno Valeriy, Yerkeldessova Gulzada, Sarzhanov Taizhan, Issaikin Dmitriy

International Journal of Electronics and Telecommunications

|

2019

|

Vol. 65, No. 3

485--490

EN

The paper analyzes the prospects for the formation and implementation of digital data transmission technologies on railways of Kazakhstan, taking into account the potential for the development of high-speed railway transport (HSRWT), as well as new approaches for solving the development problems of advanced automated dispatch control systems (ADCS). It was shown that the solution of these problems is possible by automatization of the train traffic coordination based on the use of the potential of the GPRS data transmission technology. The work further developed models and algorithms used in ADCS of the railway transport. There has been carried out the formalization of the tasks of navigation data transmission for ADCS and for the subsystems of the railway rolling stock movement coordination, including HSRWT using GPRS data transmission technology. Also, the article describes a modernized algorithm for simulation of the GPRS channels operation in ADCS. The proposed algorithm differs from the existing ones by the ability to make predictive estimates for determination of the railway rolling stock location. Also, the developed algorithm provides opportunities for coordination of the trains movement, taking into account the optimization of the GPRS resources use.

14

Simulation modeling in improving pedestrians’ safety at non-signalized crosswalks

Makarova I., Khabibullin R., Mavrin V., Belyaev E.

Transport Problems

|

2016

|

T. 11, z. 4

139--150

EN

The paper presents an analysis of road traffic accidents at non-signalized pedestrian crosswalks. A field study was conducted to determine the parameters for traffic and pedestrian flow, and construct the simulation models enabling experimentation at different loadings on the street and road network. Variants for improving the pedestrian safety at non-signalized crosswalks have been proposed. Simulation modeling of the proposed managerial decisions is expected to diminish the likelihood of road accidents. The efficiency of proposed decisions has been estimated.

RU

В статье проанализированы варианты возможных ситуаций возникновения ДТП на нерегулируемых пешеходных переходах. Проведены натурные исследования параметров движения транспорта и пешеходов на таких участках улично-дорожной сети. Определены параметры транспортных и пешеходных потоков, построены имитационные модели и проведены эксперименты на них при разных нагрузках на улично-дорожную сеть. Предложены варианты улучшения ситуации на нерегулируемых пешеходных переходах. Выполнена проверка на моделях предложенных управленческих решений, которые позволят снизить вероятность дорожно-транспортных происшествий. Выполнена оценка эффективности предложенных решений.

15

Simulation modeling of HM-networks with consideration of positive and negative messages

Naumenko V., Matalytski M.

Journal of Applied Mathematics and Computational Mechanics

|

2015

|

Vol. 14, nr 2

49--60

EN

In the article an open Queueing Network (QN) with positive and negative messages and incomes, which can be used in modeling of the behavior of viruses at the Information Systems and Networks (ISN), and also at forecasting costs taking into account virus penetration, was analyzed. Some numerical and analytical results were described on the analysis of exponential QN of the above type. It was given an algorithm of simulation modeling (SM) of HM-networks with positive and negative messages, based on the 0-point, which allows you to find incomes in such networks with arbitrary distribution of service times of positive messages. The results of the SM have been compared with the proposed analytical and numerical results. Sufficiently high accuracy of these methods was shown.

16

Simulation based investigation of different fleet management paradigms in open pit mines - a case study of Sungun copper mine

Hashemi A. S., Sattarvand J.

Archives of Mining Sciences

|

2015

|

Vol. 60, no. 1

195--208

EN

Using simulation modeling, different management systems of the open pit mining equipment including non-dispatching, dispatching and blending solutions have been studied for the Sungun copper mine. Developed model has the capability of considering detailed features of both loading and hauling equipment. Productivity assessment scenarios have been established on the constructed model and the outputs revealed the noteworthy impact of the match factor of the trucks to the loaders on the production rate by over 40%. A dispatching simulation model with the objective function of minimizing truck waiting times have been developed and 7.8% improvement obtained by applying a flexible assignment of the trucks for the loaders compared to the fixed assignment system. Finally ore grade blending control unit has been introduced into the model. Getting the advantages of the newly added module it became possible to monitor the portion of material excavated from different operating benches and control truck dispatching rules for keeping the overall ore grade exactly at desired value.

PL

Przy użyciu modeli symulacyjnych zbadano różnorodne systemy zarządzania flotą pojazdów i urządzeń w kopalni odkrywkowej (wydawanie dyspozycji przewozu, wstrzymywanie przewozu oraz rozwiązania kwestii mieszania o rud o różnej zawartości pierwiastka użytecznego) na przykładzie kopalni miedzi Sungun. Opracowany model uwzględnia szczegółowe cechy sprzętu przeładunkowego oraz transportowego. Na podstawie modelu opracowano następnie scenariusze oceny wydajności, a wyniki jednoznacznie wykazały wielką wagę odpowiedniego skojarzenia ilości pojazdów i ładowarek. Opracowano model symulacyjny kierowania urządzeń do pracy, jako funkcję celu przyjmujący minimalizacje czasu przestoju ciężarówek. Uzyskano wynik lepszy o 7.8% poprzez elastyczne przydzielania pojazdów do ładowarek w porównaniu do systemu trwałego ich do siebie przypisania. W ostatnim etapie dodano do modelu system kontroli procesu mieszania rud o rozmaitej zawartości pierwiastka użytecznego. Korzystając z nowo-dodanego modułu, możliwe stało się monitorowanie porcji materiału wybieranego z poszczególnych poziomów i kontrolowanie rozsyłanych ciężarówek tak, by w skali całej kopalni możliwe było ciągłe utrzymanie zawartości pierwiastka użytecznego na żądanym poziomie.

17

Modelling of transport-and-handling sites operation within metallurgical enterprises

Parunakjan V., Aksenov M., Sizova E.

Transport Problems

|

2013

|

T. 8, z. 3

121--129

EN

In terms of existent regime of transport-and-handling sites operation, the necessity in enhancing the efficiency of production and transport interaction is justified. For this purpose simulation model of transport-and-handling site, which provides reception of raw materials, is developed.

RU

Обоснована необходимость повышения эффективности взаимодействия производства и транспорта в рамках существующего режима функционирования транспортно-грузовых комплексов металлургических предприятий. С этой целью разработана имитационная модель транспортногрузового комплекса приёма сырья.

18

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

Wiśniewski T., Rymaszewski S.

Applied Computer Science

|

2013

|

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.

19

Simulation modeling of stationary systems reliability

Wesołowski Z.

Studia Informatica : systems and information technology

|

2012

|

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.

20

About simulation modeling of HM-queueing network with unreliable systems

Matalytski M., Statkevich S.

Prace Naukowe Instytutu Matematyki i Informatyki Politechniki Częstochowskiej

|

2012

|

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.