Wyniki wyszukiwania - Biblioteka Nauki

1

Agent Systems as Modern methods in the Simulation Tools

100%

Topolska K.

Logistics and Transport

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2011

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tom 13

117-122

EN

Modern computer simulation tools are based on different mathematical models. The simplest of these models are rank as rigid computational methods like statistics or probability mathematics. To flexible, more complex computational methods we can classify artificial neural systems, genetic algorithm or fuzzy sets. Without doubt usage of this second group of models are becoming more universal. They are classified as methods of artificial intelligence. With regard to their mechanisms of teaching, neural systems are used for the purpose of optimization. They allow to describe different non-linear structure of the data and to classify them in the appropriate way. Statistic methods do not show optimum results in the non-linear spaces and spaces that are dimensionally complex. Agent methods that are used in the intelligent systems make possible to precisely simulate reality. Reality with huge amount of objects that are on the different level of abstraction. They are used for example in rout planning by means of GPS system, in the planning different logistic processes, in the economics, in the forecasting of meteorological phenomenons etc. Common feature of all forecasting methods are mistakes connected with discrepancy of simulation results and real value. In the literature there is no researches in mentioned discipline. Results of optimization presented in the article are obtained using agent systems. These results refer to finding the shortest way to the defined extreme by studying level of route complexity (multiple, amount of extremes), time of studying, mistakes of defining appropriate extreme. To authenticate results in case of different tools to simulation, researches have been conducted with five different simulation computer programs.

2

On the application of the appropriate type of simulators for the specific learning objectives

100%

Kluj S.

Polish Maritime Research

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2002

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tom Vol. 9, nr 1

3-8

EN

This paper presents a proposal of classification of the engine room simutators. Its main subject is the relation between proposed simulator types and the learning objectives specified in the STCW International Convention. It was also proved that in some cases the full mission simulator is not the best tool for the specific training tasks. Finally, the problem of simulator compliance with the provisions of STCW International Convention was discussed.

3

Simulation of Security Protocols based on Scenarios of Attacks

100%

Jakubowska G. , Dembiński P. , Penczek W. , Szreter M.

Fundamenta Informaticae

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2009

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tom Vol. 93, nr 1-3

185-203

EN

In this paper we offer a methodology allowing for simulation of security protocols, implemented in the higher-level language Estelle, using scenarios designed for external attacks. To this aim we apply a translation of specifications of security protocols from Common Syntax to Estelle and an encoding of schemes of attacks into Estelle scenarios. We show that such an intelligent simulation may efficiently serve for validating security protocols.

4

On the Expressiveness of Communication Channels for Object Nets

100%

Köhler-Bußmeier M. , Heitmann F.

Fundamenta Informaticae

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2009

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tom Vol. 93, nr 1-3

205-219

EN

In this work we present object net systems, i.e. Petri nets with nets as token objects, which are equipped with channels that allow to transfer net-tokens in the vertical dimension of the nested marking. These channels are a modelling element powerful enough to describe a direct simulation of counter programs which shows that typical net problems like boundedness, coverability, and reachability are undecidable.

5

Parametry procesu rozpęczania rury falowanej

100%

Stadnik R. , Kazanecki J. , Szymański J.

Przegląd Mechaniczny

|

2007

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tom nr 7-8

33-36

PL

Prawidłowe warunki procesu rozpęczania rury falowanej są niezwykle ważne i mają ogromny wpływ na własności elementu gotowego. Jest wiele czynników, które w sposób bezpośredni wpływają na jakość wyrobu końcowego. Zaliczyć można do nich m.in.: grubość ścianki rozpęczanej rury, ciśnienie wewnętrzne zadane w trakcie rozpęczania oraz przemieszczenie matryc segmentowych przy fałdowaniu. W pracy przedstawiono symulacje numeryczne procesu rozpęczania rury falowanej oraz ich doświadczalną weryfikacje w warunkach przemysłowych. W trakcie symulacji numerycznych rozpatrywano najważniejsze parametry procesu oraz ich wpływ na wyrób końcowy. Gotowy element wykonany ze stali odpornej na korozję ma zastosowanie w układzie wydechowym samochodu osobowego.

6

Simulation of urban traffic lights control

100%

Amborski K. , Dzieliński A. , Kowalczuk P.

Logistyka

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2010

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tom nr 2

EN

Simulation of traffic control is nowadays very important for dealing with increasing urban traffic. It helps to construct the strategy of traffic lights switching and determine alternative path in the case of an accident or traffic jam. In the paper we present the application of simulation tool DYNASIM being prepared by French company DYNALOGIC. It has big number of alternative possibilities in modeling of crossings and conditions. In the paper will be described exemplary simulation of chosen crossings in Warsaw with choice of several different conditions. The simulation package can be free available for universities for educational use.

PL

Symulacja sterowania ruchem drogowym jest obecnie bardzo ważnym elementem w związku z rosnącym ruchem w miastach. Pomaga ona budować strategię działania w ustaleniu przełączeń świateł drogowych i wyznaczaniu alternatywnych dróg transportu w przypadku kolizji lub zatorów. W referacie przedstawiamy zastosowanie narzędzia symulacyjnego DYNASIM przygotowanego przez francuską firmę DYNALOGIC. Oprogramowanie to ma wiele alternatywnych możliwości modelowania skrzyżowań i warunków ruchu. W referacie opisana jest przykładowa symulacja wybranych skrzyżowań w Warszawie z wyborem kilku zestawów warunków. Pakiet symulacyjny może być nieodpłatnie udostępniony uniwersytetom dla celów edukacyjnych.

7

Simulation Complexity

100%

Hay N. J.

Fundamenta Informaticae

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2008

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tom Vol. 83, nr 1-2

117-140

EN

In Algorithmic Information Theory, the algorithmic complexity of a sequence is the length of the shortest program which generates it. Is there a measure of the complexity of a computer? We define the simulation complexity of a computer to be the least cost of simulating that computer on a fixed universal computer. We generalise this to processes, computers which can have potentially infinite output (e.g. monotone Turing machines). This measure has monotone complexity as a special case. Simulation complexity has applications to sequence prediction, leading to a clarification of a central prediction error inequality and a stronger form of dominance. Enumerable semimeasures are functions which represent sequence predictors. These semimeasures can be in turn represented by processes. A universal process generates a universal semimeasure: one that outperforms any other predictor but for a cost depending on how complex that predictor is. This extra cost is exactly the simulation complexity of the predictor.

8

Simulation as a method of choosing the order picking concept

100%

Gałązka M. , Jakubiak M.

Logistics and Transport

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2010

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tom Vol. 11, No. 2

81-88

EN

The analysis of the three, main, heuristics approaches outlining the order picking routes in a warehouse, is a subject of this paper. Order picking is the most laborious warehouse process and it contributes to 55% - 65% of all the costs of operations performed in a warehouse. The most time consuming order picking activity, according to the research, is transfer which is closely related to, adopted by a given company, system of transfer and movement between the points of taking the order, places of pick up, and points of release. Even the small shifts of commodities, on short distances, play a very important part in modern dynamic economy. On the basis of a simple model of a warehouse owned by an authentic company, a computer program was created, which helps in simulation of the three, main heuristics approaches to outline the routes, so as to make the order picking process as short as possible.

9

Verification of Timed Automata Based on Similarity

100%

Dembiński P. , Penczek W. , Półrola A.

Fundamenta Informaticae

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2002

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tom Vol. 51, nr 1,2

59-89

EN

The paper presents a modification of the standard partitioning technique to generate abstract state spaces preserving similarity for Timed Automata. Since this relation is weaker than bisimilarity, most of the obtained models (state spaces) are smaller than bisimilar ones, but still preserve the universal fragments of branching time temporal logics. The theoretical results are exemplified for strong, delay, and observational simulation relations.

10

Application of computer modeling and simulation methods in verification of a system of additional armour installation

100%

Morka A. , Stanisławek S. , Niezgoda T. , Rudnik D.

Szybkobieżne Pojazdy Gąsienicowe

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2016

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tom nr 1 (39)

183--190

EN

The paper discusses the problem of verifying systems of additional armour installation with the use of computer modelling and simulation methods. To achieve this purpose, numerical models of essential structural elements of the fastening arrangement, of the panel and of the representative portion of hull plate have been developed. Suitable constitutive models of the materials used and proper parameters thereof have been selected. Tested panels were subjected to group N11 standard loads in accordance with the Defence Standard NO-06-A 103/2005 and AP 14.5x114 mm B32 projectile impact in accordance with the guidelines included in STANAG 4569. The results obtained by means of numerical analyses were studied in particular in terms of establishing the probability of permanent plastic deformations in the elements of the additional armour fastening system. It was found that in the cases studied the impact of a projectile results in permanent (plastic) deformations in the fastening arrangement elements (bushings, welds), but in quantitative terms these were far from destructive. No disturbing stresses or strains have been identified in bolts, washers and threaded connections. The only situation that needs to be looked into are permanent strains in the crush area of blind rivet nuts observed for loads from single and repeated impacts. Analysis of the impact of an AP 14.5 projectile centrally along the axis of the bolt of the fastening arrangement showed lack of protective capacity in this area. The projectile perforates elements of the fastening arrangement with no significant resistance, while its energy decreases only slightly and thereby the threat of hull penetration is still retained.

11

Nowe doświadczenie wojny This War of Mine

85%

Piotrowiak M.

Śląskie Studia Polonistyczne

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2017

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tom 9

|

nr 1

51-68

EN

The article undertakes a polemological reflection which is not limited to historiography and philosophy of history, being an attempt at reaching multidimensional and non-standard vision of war. It may seem that studying a computer simulation of people’s lives during the war conflict is far from what a literary scholar should be doing. Nevertheless, This War of Mine redefines the notion of computer games and of classically defined agon. The interactive production of Warsaw 11 bit studios becomes a pretext for studying the ways in which new media refer to literature. The unique experience of war depicted by This War of Mine draws from literary testimonies but at the same time it captures more than literature could ever do. Is the “word in play” the missing link of Bachtin’s equation?

12

Cutting Force Reduction in The Milling of Aluminum Alloys with Serrated Cutting Tool Edges

80%

Rekers S. , Auerbach T. , Veselovac D. , Klocke F.

Journal of Machine Engineering

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2015

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tom Vol. 15, No. 4

27--36

EN

Structural components for aerospace industry are in most cases milled from solid. Usually more than 80 % of the bulk material is removed by milling processes in order to obtain the parts final shape. Due to economic aspects, high material removal rates are desired to reduce cost intensive machine cycle times. In order to meet high process design demands, optimized cutting forces at maximized material removal rates are of crucial interest. These are especially depending on the work piece material to be machined, the cutter work piece engagement conditions as well as the milling cutters geometry. The usage of milling tools with serrated cutting edge geometries enables a significant reduction of cutting forces. In this article, cutting forces during milling aluminum alloys using different serration geometries and engagement conditions are investigated. At first, a generic cutting force model is introduced. The required model parameters are approximated for the machined material by subsequent milling tests employing non-serrated cutters. In a second step, a model is presented allowing a time-domain simulation to obtain cutting force variations for cutters with serrated cutting edges. Finally, experimental data for different serrated cutters are compared with the simulated predictions.

13

The Ni-Al-Hf Multiphase Diffusion

80%

Romanowska J. , Wierzba B. , Markowski J. , Zagula-Yavorska M. , Sieniawski J.

Archives of Metallurgy and Materials

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2016

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tom Vol. 61, iss. 2A

587--592

EN

The generalized Darken method was applied to simulate the diffusion between γ-Ni| γ’-Ni3Al and γ’-Ni3Al|β-NiAl interfaces. The results of calculations were compared with the experimental concentration’s profiles of nickel, aluminum and hafnium in aluminide and hafnium doped aluminide coatings deposited by the CVD and PVD methods on pure nickel. The method deals with the Wagner’s integral diffusion coefficients and thermodynamic data - activities of components. The experimental results agree with the simulated ones.

14

Deteriorating products shipments planning improving

80%

Rojkov M.

Research in Logistics & Production

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2013

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tom Vol. 3, No. 4

287--299

EN

The wastage minimization problem of products with limited expiration date keeping required service level is studied. Short literature review is presented. Major approaches for deteriorating stock planning are listed. Some related researches are provided. The problem is stated considering industry specifics of non from concentrate juice production. The drawbacks of initial planning approach are shown. Some market conditions and business processes influencing supply chain performance are presented. The algorithm for wastage volume estimation is developed. It is shown that the shipments planning process paying attention to product limited shelf life may reduce the costs significantly, despite that in certain situations it may be better to consider product delisting. The safety stock level affects the system's performance indicators greatly, but is hard to calculate analytically. The vba-excel-based tool for the products shipment planning is developed, analyzed and implemented. The simulation model reflecting the planning tool logic is developed. Several simulation experiments are performed.

15

Interdisciplinary use of simulation of passenger vehicle for teaching at the academic level

80%

Orszulak B. , Merkisz J.

Journal of Mechanical and Transport Engineering

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2014

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tom Vol. 66, No. 4

49--55

EN

Potential and current students of universities more and more often pay attention to the quality and level of classes as part of their studies. It is an important issues for the faculties, institutes and other units which make up the educational path of the educational profile. Use of above all an unusual approach to activities and utilization of the modern equipment like a passenger vehicle simulator AS1200-6 company AutoSim, to correlate and analysis by students of various data collected and the results. It is an important element of activating students by inteesting them of topic. The article presents a description of the positions, primary and secondary goals which are to achieve the students after successful completion of laboratory exercises, the methodology and the concept of teaching for undergraduate students in the field of simulation studies the impact of driving style on emissions vehicle (ecodriving) and the main problems associated with the proper functioning classes.

PL

W artykule przedstawiono opis stanowisk, podano cele główne i dodatkowe jakie mają osiągnąć studenci po poprawnym wykonaniu ćwiczenia laboratoryjnego, metodykę oraz koncepcję prowadzenia zajęć dla studentów pierwszego stopnia z zakresu badań symulacyjnych wpływu stylu jazdy na poziom emisji pojazdu (eco-driving), a także scharakteryzowano główne problemy związane z właściwym prowadzeniem zajęć. Określono cele do osiągnięcia przez grupę studentów podczas zajęć i na tej podstawie opracowano program zajęć. Przedstawiono podział Sali laboratoryjnej ze względu na funkcjonalność i bezpieczeństwo. Wykazano możliwość wykorzystania stanowiska symulacyjnego do interdyscyplinarnych prac badawczo-naukowych.

16

Simulation of Superfinished Surface Formation

80%

Görög A.

Advances in Science and Technology. Research Journal

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2021

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tom Vol. 15, no 2

219--227

EN

The article deals with the simulation of single-oscillating grooves superfinishing. A model of the superfinishing tool was created according to the input information about the tool and the superfinishing process. Using this tool, a simulation of the cutting process was performed. The input parameters for the simulation were the cutting conditions, which determined the paths of tools individual grains (process kinematics). The simulation is realized by gradual removal of the workpiece material by individual grains of the tool. The result of the simulation is the profile of the superfinished surface at an evaluation length of 1.25 mm. It is possible to determine the surface roughness parameters from the profile. Creating and displaying multiple profiles side by side creates a graphical model of the superfinished surface. The simulation can be used for numerical simulation experiments, where both material and energy are saved. The article presents one such experiment together with the results – the surface roughness was influenced by individual factors. The simulation results (surface roughness parameters and surface appearance) were compared with the real superfinished surface on the outer ring of the bearing. This surface was manufactured under mass production conditions. The comparison confirmed that a simulation is a suitable tool for research of abrasive machining methods. At the end of the article is a discussion about a possible improvement of the simulation - considering 3D grains of the tool.

17

Simulation evaluation of the influence of selected geometric parameters on the operation of the pneumatic braking system of a trailer with a differential valve

80%

Szpica D. , Kisiel M. , Czaban J.

Acta Mechanica et Automatica

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2022

|

tom Vol. 16, no. 3

233--241

EN

This article presents simulation models of trailer air brake systems in configurations without a valve and with a differential valve, thus demonstrating the rationale for using a valve to improve system performance. Simplified mathematical models using the lumped method for systems without and with a differential valve are presented. The proposed valve can have two states of operation depending on the configuration of relevant parameters. These parameters can include the length of the control pipe, the throughput between chambers in the control part of the valve and the forcing rise time. Based on the calculations, it was found that the differential valve with large control pipe lengths can reduce the response time of the actuator by 42.77% relative to the system without the valve. In the case of transition of the valve to the tracking action, this time increases only by 9.93%. A force rise time of 0.5 s causes the transition of the valve from the accelerating action to the tracking action, with 9.23% delay relative to the system without a valve. The calculations can be used in the preliminary assessment of the speed of operation of pneumatic braking systems and in the formulation of guidelines for the construction of a prototypical differential valve. In conclusion, it is suggested to use a mechatronic system enabling smooth adjustment of the flow rate between chambers of the control system of the differential valve.

18

Wpływ uproszczeń w badaniach symulacyjnych zderzeń pocisków z tarczą na dokładność wyników

80%

Stanisławek S. , Morka A. , Niezgoda T.

Biuletyn Wojskowej Akademii Technicznej

|

2013

|

tom Vol. 62, nr 3

137-143

PL

Artykuł omawia zagadnienie możliwości stosowania określonych uproszczeń w symulacji komputerowej. Stanowi on niezbędny warsztat dla każdego badacza stosującego opisane sposoby modelowania. Weryfikacja uproszczeń numerycznych polegała na przeprowadzeniu trzech testów zderzeniowych dla rdzenia pocisku 7,62 × 51 WC oraz czwartej symulacji polegającej na porównaniu efektów uderzenia pełnego modelu pocisku oraz jedynie jego rdzenia. Opracowane modele tarczy symulowały materiał stalowy z wprowadzonymi typowymi parametrami, natomiast pocisk był opisany modelem Johnsona-Cooka. Prędkość początkowa pocisku wynosiła 854 m/s, zaś tarcza pozostawała nieruchoma i zamocowana w płaszczyźnie prostopadłej do kierunku lotu. Opisane badania potwierdzają możliwość stosowania modelu materiału nieodkształcalnego oraz sprężystego do uproszczonego opisu ciał materialnych. Pozwala to na uproszczenie i przyspieszenie obliczeń numerycznych w sytuacjach, gdzie materiały zderzających się ciał mają znacznie różne właściwości mechaniczne. Z dużą ostrożnością powinno się odnosić do odczytywania sił rejestrowanych na ściance nieodkształcalnej. Analiza sił oraz energii pokazuje natomiast, że sabot i płaszcz pocisku nie odgrywają zasadniczej roli przy uderzeniu w nieruchomą tarczę. Doznaje ona większego popędu, jednak nie jest to różnica zasadnicza.

EN

The paper presents the possibility of applying certain simplifications for computer simulations. It is the essential knowledge for each scientist employing the described methods of modelling. Verification of numerical simplifications consisted in conducting three impact tests for a 7.62 × 51 WC projectile core and a forth one which referred to a comparison of a full model of the penetrator with its core only. The target was described with a simple steel material while the projectile with an advanced Johnson-Cook model. Projectile initial speed was 854 m/s while a target remained motionless and fixed in a plane perpendicular to the motion direction. The performed tests confirm the possibility of using rigid and elastic materials for a simplified material body description. It allows simplification and shortening of computational time when materials are characterized by very different strength. However, a user should be very careful when analyzing the forces recorded on a rigid wall. Furthermore, analysis of the forces and energies shows that both a sabot and a jacket do not play a significant role during the impact into a motionless target. It register a bigger force impulse but it is not a substantial difference.

19

Numerical analysis of heat conduction influence on SCR aftertreatment systems EFF

80%

Bachanek J. , Rogóż R. , Teodorczyk A.

Journal of KONES

|

2018

|

tom Vol. 25, No. 3

51--58

EN

Selective Catalytic Reduction (SCR) is well known method for reducing NOx emission in diesel engine exhaust gas. Urea-water solution (UWS) injected into hot stream decomposes due to thermolysis into ammonia and isocyanic acid which hydrolyses further into more ammonia and carbon dioxide. Resultant ammonia is the NOx reductor, producing water vapour and carbon dioxide from the reduction reaction. To provide sufficient NOx reduction efficiency, UWS needs to be properly atomized and mixed with exhaust gas. However, due to more and more restrictive emissions regulations provided by European Union and Close Coupled trend of aftertreatment systems in vehicles the design process is very complex and demanding. Computational Fluid Dynamics (CFD) simulations are integral part of product development, allowing save time and reduce costs of preparing prototypes for further tests. However, it is necessary to understand all the processes and problems connected with NOx reduction in SCR system. Strong turbulent flow of hot stream gas, urea-water solution spray injection, droplets interaction with wall, wallfilm generation are included. The objective of this work is to investigate the impact of heat transfer modelling inside mixing elements of SCR system on urea mixing uniformity and wallfilm deposit on the walls of the system. Simplified and more complex approach is compared with no heat transfer cases. All the simulations were conducted using AVL FIRETM software. Results showed that wall heat transfer might have an impact on mixing efficiency and wallfilm formulation. It is necessary to take into account the effect of mixing elements heat conduction in CFD simulations during the aftertreatment design process.

20

Deep learning classification and recognition method for milling surface roughness combined with simulation data

80%

Lu L. , Yi H. , Shu A. , Qin J. , Lu E.

Metrology and Measurement Systems

|

2023

|

tom Vol. 30, nr 1

117--138

EN

To address the problem that a deep neural network needs a sufficient number of training samples to have a good prediction performance, this paper firstly used the Z-Map algorithm to generate a simulated profile of the milling surface and construct an optical simulation model of surface imaging to supplement the training sample size of the neural network. Then the Deep CORAL model was used to match the textures of the simulated samples and the actual samples across domains to solve the problem that the simulated samples were not in the same domain as the actual milling samples. Experimental results have shown that high texture matching could be achieved between optical simulation images and actual images, laying the foundation for expanding the actual milled workpiece images with the simulation images. The deep convolutional neural model Xception was used to predict the classification of six classes of data sets with the inclusion of simulation images, and the accuracy was improved from 86.48% to 92.79% compared with the model without the inclusion of simulation images. The proposed method solves the problem of the need for a large number of samples for deep neural networks and lays the foundation for similar methods to predict surface roughness for different machining processes.