Simulation modelling

Federated simulations address the need for interoperability, as well as the improvement of reuse and composability of existing simulation models. The focal goal in a federated simulation is to facilitate composable simulations by standardizing interfaces to enable at least the technical interoperability among disparate simulations. Yet, existing federated simulation infrastructures neither facilitate sound reasoning about substantive interoperability nor are dynamically extensible. Emergent web services technologies hold out the potential to significantly improve the development of interoperable, extensible, and dynamically composable federations. As such, the recent XMSF initiative urges the use of a set of Web-based technologies that can be applied within an extensible framework for next generation of modeling and simulation applications to interoperate. We discuss how the realization of multimodel and multisimulation formalisms in terms of semantic web and agent technologies may ...

The employment of network-based technologies, such as the WWW and middleware platforms, significantly increased the complexity of distributed application, as well as the Quality of Service requirements for the underlying network. Distributed application modelling is nowadays far more demanding than network modelling, where numerous solutions are already employed in commercial tools. We introduce a simulation modelling approach for distributed systems, giving emphasis to distributed applications. The proposed scheme enables the in-depth description of application functionality, the accurate estimation of network load and the extension of existing application models to support further customisation. It supports widely employed architectural models, such as the client-server model and its variations, and is based on multi-layer decomposition. Application functionality is described using predefined operations, which can be further decomposed into simpler ones, ultimately resulting into elementary actions corresponding to primitive network operations, such as transfer and processing. Even if realisation of this scheme proves to be time demanding, individual application modelling is performed with consistency and considerably lower overhead. The distributed system simulation environment built to realise the proposed modelling scheme and a case study indicating key features of the overall approach are also presented.

Doutoramento em Matemática Aplicada à Economia e GestãoThe inevitability of taxes and regulations, that cause agents to go underground, forces the authorities to tolerate some underground economic activity and grants the underground economy natural features. The natural level of the underground economy is defined as the level of underground economic activity in the decentralized equilibrium, provided that the actual structural characteristics of the economy and social preferences are accounted for by imbedding them in the Walrasian system of general equilibrium equations. Its existence is proven using two variants of neoclassical general equilibrium models. The underground economy is found to influence the successfulness of fiscal consolidation programmes, depending on the position of the economy relative to critical fiscal thresholds associated with the natural level of the underground economy. Tax increases yield higher tax proceeds up to the threshold, and lower tax proceeds, pas...

The use of simulation modelling techniques in studies of technological innovation dates back to Nelson and Winter's 1982 book, An Evolutionary Theory of Economic Change. Four main issues are identified in reviewing the key contributions in this burgeoning literature. First, a key driver in the construction of computer simulations has been the desire to develop theoretical models capable of dealing with the complex phenomena characteristic of technological innovation. Second, no single model captures all of the dimensions and stylized facts of innovative learning. The article develops a taxonomy that distinguishes between these dimensions and clarifies the different perspectives underpinning the contributions made by mainstream economists and nonmainstream, neo-Schumpeterian economists. Third, the simulation models are heavily influenced by the research questions of these different schools of thought. Finally, attention is drawn to the difference between learning and adaptation w...

This paper presents a framework for understanding and improving the process of simulation model building involving a group of domain experts, classifying the different roles the model may play at various stages of its development. We argue that a consideration of these different roles will help modelling consultants to better design modelling processes to meet the needs of their clients and clients to better understand what a modelling project can achieve, so that ultimately projects are more successful. The framework consists of four different "object roles," defined along two dimensions: firstly a functional dimension (boundary object vs. representational object) and secondly, a knowledge dimension (epistemic object vs. technical object). We show how the same simulation model can take different roles at different stages during the group model development process according to the needs of the group. For example, the model could be used for facilitating communication, gaining understanding and insight into the real-world system, or for experimentation and policy evaluation. The use of the framework is illustrated by two case studies in health care, based in the UK National Health Service (NHS). Its relevance and applicability are then examined through a survey on model use in expert group model building exercises. While both case studies used system dynamics, the framework is applicable across a range of modelling techniques. The survey on model use was conducted among a group of modelling consultants with experience of using both discrete-event simulation and system dynamics within the NHS, and indicated the usefulness of the framework in describing group model building processes.

At the development stage of a product, target cost management has a significant effect on achievement and maintenance of product competitiveness in a given market and the desired target profit as the primary aim of production. Target cost management, i.e., target profit management, is performed by evaluating individual variations of a conceptual and preliminary design solution for a new product and by choosing the solution with the lowest development costs. The paper presents the use of Adaptive Neural Fuzzy Inference System model for managing development costs on the example of double-row angular contact ball bearings as an example of applying the above approach to market positioning in relation to competitors.

Managing the costs of a product life cycle, which is performed at the stage of its development, has a dominant influence on achieving and maintaining the competitiveness of the product in the market and the target profit as the primary production goal. Development is of crucial importance in the product life cycle, because evaluating individual solutions for the new product's conceptual and preliminary design based on the simulation of costs of all stages of its life cycle represents the way of ensuring the design requirements for excellence. This paper presents in detail the setting and development of a hybrid model of product life cycle cost management, based on fuzzy neural networks.

In such drought-prone regions as Kazakhstan, research on regional drought characteristics and their formation conditions is of paramount importance for actions to mitigate drought risks caused by climate change. This paper presents the results of research on the spatio-temporal patterns of atmospheric droughts as one of the most important factors hindering the formation of crop yields. The influence of several potential predictors characterizing teleconnection in the coupled "atmosphere-ocean" system and cosmic-geophysical factors affecting their formation is analyzed. The spatial relationships between atmospheric aridity at the individual stations of the investigated area and the wheat yield in Kazakhstan as well as its relationships with potential predictors were determined using econometric methods. High correlation was shown between wheat yield fluctuations and Multivariate El-Niño-Southern Oscillation (ENSO), galactic cosmic radiation, solar activity, and atmospheric drought expressed through the soil moisture index, which in turn depends on precipitation levels and temperatures. The model could be modified further so that the individual components could be forecasted into the future using various time series in an ARIMA model. The resulting integration of these forecasts would allow the prediction of wheat yields in the future. The obtained results can be used in the process of creating effective mechanisms for adaptation to climate change and droughts based on their early diagnosis.

While an experimental approach is suitable to understand the differences between bowlers it is not suitable to understand the changes required to optimise an individual's performance. To optimise individual performance a 16-segment computer simulation model of the front foot contact phase of fast bowling was developed, customised to an elite fast bowler and evaluated. Optimising technique via the torque generator activation timings and the initial body configuration technique found increases in performance of 10% and 22%,respectively, where the optimal technique consisted of a straighter front knee, more delayed bowling and non-bowling arms and increased trunk flexion. The effect of increasing strength by 5% was shown to only increase ball speed by 1%. It was concluded that this individual's performance is limited by technique and this should be his area of focus for improvement.

In this work the Si self-interstitial-carbon interaction has been experimentally investigated and modeled. The interactions between self-interstitials, produced by 20-keV silicon implantation, and substitutional carbon in silicon have been studied using a Si 1Ϫy C y layer grown by molecular beam epitaxy ͑MBE͒ and interposed between the near-surface self-interstitial source and a deeper B spike used as a marker for the Si-interstitial concentration. The C atoms, all incorporated in substitutional sites and with a C-dose range of 7ϫ10 12 -4 ϫ10 14 atoms/cm 2 , trap the self-interstitials in such a manner that the Si 1Ϫy C y layer behaves as a filtering membrane for the interstitials flowing towards the bulk and, consequently, strongly reduces the boron-enhanced diffusion. This trapping ability is related to the total C dose in the Si 1Ϫy C y membrane. Substitutional carbon atoms interacting with self-interstitials are shown to trap Si interstitials, to be removed from their substitutional sites, and to precipitate into the C-rich region. After precipitation, C atoms are not able to further trap injected self-interstitials, and the interstitials generated in the surface region can freely pass through the C-rich region and produce B-enhanced diffusion. The atomistic mechanism leading to Si-interstitial trapping has been investigated by developing a simulation code describing the migration of injected interstitials. The simulation takes into account the surface recombination, the interstitial diffusion in our MBE-grown material, and C traps. Since the model calculates the amount of interstitials that actually react with C atoms, by a comparison with the experimental data it is possible to derive quantitative indications of the trapping mechanism. It is shown that one Si interstitial is able to deactivate about two C traps by means of interstitial trapping and C clustering reactions. The reaction causing trapping and deactivation is tentatively described.

Most of the frameworks or assistance systems for experiment specification do not provide a process explicitly based on formally specified hypotheses. This deficiency leads to inaccurate or insufficient record of an experiment, decreasing the trustworthiness and reproducibility of the experiment. Moreover, the wide variety of models, metamodels, tools, and data for experimentation requires Global Model Management (GMM) that is utilizing Model-Driven Engineering techniques, facilitates documentation, sharing, reusability, and replicability of simulation experiments. In this study, we strive to illustrate how to support simulation experimentation with hypotheses as a scientific workflow through GMM with an extension to the Simulation Experiment Description Mark-up Language (SED-ML). In particular, we present a megamodel built to serve as a repository to manage the artefacts employed in a simulation experiment. Based on the SED-ML, and enriched with hypothesis handling, our megamodel attempts to address all the phases of a simulation experiment, including specification, input data generation, execution, and output data analysis.

In this paper, we focus on the global design of an active micro-catheter, which is fully in the scope of medical needs for near future, and on the electroformed realization of one of its shape memory alloy (SMA) actuators. Virtual prototyping is a powerful tool for designing manufactured objects and will be described here with respect to the goal application. In the medical domain indeed, one major demand is to dispose of active catheters to help in surgical exploration and interventions. For this reason, we develop, in collaboration with the Laboratoire de Robotique de Paris, such a micro catheter provided with micro actuators. This catheter has to be agile and thin enough to crawl its way into complex environment (human ducts). For this reason, we have chosen to use articulated links in its design. So we address this design by means of a virtual prototype especially developed, including the interaction with a duct model obtained by scanner and provided with an haptic interface. A description of an original simulation platform is also proposed. Then we present a part of the realization of the real prototype by studying, with plans of experiment, the machining of a Shape Memory Alloy spring, which will be used in the active part of the actuators. de Robotique de Paris un tel endoscope équipé de micro-actionneurs. Cet endoscope doit être suffisamment agile et fin pour pouvoir évoluer dans un environnement complexe (conduits humains). Pour ces raisons nous avons choisi de développer un système polyarticulé. Nous améliorons par la réalisation d'un prototype virtuel incluant l'interaction avec un modèle de conduit issu de scanner, et dirigé par une interface haptique. La simulation s'appuie sur une plate-forme originale que nous décrivons. Nous présentons ensuite une partie de la réalisation du prototype réel à travers l'étude par plans d'expérience de la fabrication de ressorts en AMF qui seront utilisés pour actionner le système.

One of the major problem for the identification of industrial multi-input muti-output (MIMO) systems is the too small variance of some signals collected during several experiments. Usually, sufficient information exist but are often dispersed among many data-files. In this case, it is difficult to conciliate this information to build a single well adapted model. The ALS procedure (Alternate Least Squares) has been performed in order to solve this kind of problem. In the first part of this paper, the authors present the principle of the ALS procedure ; the details of the complete algorithm are given in part two. Then, ba sed on some examples, a comparison of the Prediction Error Method (PEM) with our new method is presented.

One of the major problem for the identification of industrial multi-input muti-output (MIMO) systems is the too small variance of some signals collected during several experiments. Usually, sufficient information exist but are often dispersed among many data-files. In this case, it is difficult to conciliate this information to build a single well adapted model. The ALS procedure (Alternate Least Squares) has been performed in order to solve this kind of problem. In the first part of this paper, the authors present the principle of the ALS procedure ; the details of the complete algorithm are given in part two. Then, ba sed on some examples, a comparison of the Prediction Error Method (PEM) with our new method is presented.

A new corresponding states model for predicting the viscosity of heavy crude oils and petroleum fractions is proposed in this work. The model uses decane and eicosane as reference components for petroleum fractions of average molecular weight higher than 142. The viscosity of a component or fraction may be obtained from the viscosities of these two reference fluids (decane and eicosane) a t the same reduced temperature and reduced pressure using the molecular weight as an interpolation parameter. This model showed better accuracy in predicting the viscosity than the model that uses one reference (methane) or two references (methane and decane), when the molecular weight is higher than 142. The present model, when tested on 187 data points for 29 undefined heavy petroleum fractions from 15 worldwide crudes, yielded an overall deviation of 5.3%. Testing of the model on 53 data points for seven crude oils from offshore Abu Dhabi yielded an average absolute deviation of 5.9%.

In micro-hybrid vehicles, the starter battery is subject to heavy cyclic loads. Results of these cyclic loads are vertical concentration gradients (acid stratification). For this study, it was analyzed systematically how different temperatures influence the formation and reduction of acid stratification. To this end, flooded lead-acid batteries were cycled during a cycle test with 17.5% depth of discharge at -5 • C, 3 • C, 27 • C, and 60 • C. To determine the extent of acid stratification caused by the cycling, the acid density values of the test batteries cycled at four different temperatures were measured using acid density monitoring. The acid densities were measured hourly in 0%, 15%, 30%, 45%, 60%, 80%, and 100% sections in the direction of the perpendicular z-axis of the battery. The measurements showed that the extent of acid concentration gradients is dependent on the temperature, with acid stratification caused by an uneven distribution of current over the height of the plates. Furthermore, it was established that battery discharging as well as battery charging causes an inhomogeneous acid density distribution in the battery electrolyte.

Nowadays the implication of vast spread discrete organization systematic operational function units of businesses has contributed immensely to the development of general corporate system integration aids interdependence between different communication service model or nodes, thereby equipping the system improvising enhancement metrics embedment to override impediment of organizations methods of accessibility at the discrete vast workspace of the organization, these impasses was boycotted as led to the introductory emergence of systematic evolution of modeling application to a universal or specific unified system called simulation and modeling, whereby it has majorly contribute to the imitation of real-time environment that is supposed to be a unified cooperate entity, in which a computer is implemented to imitate the process and the facilities of setups unit in the organization. As a step up in industrial modeling, the integration of evolutionary mathematical modeling bridges the intricacy process and interrelationship process, and thereafter leads to further predicting the outcome of the process so that it can be easy for the analyst to focus on the system's measure of performance. Meanwhile, the facilities or the process of interest are known as a system.

Micro-electro-mechanical-systems (MEMS) are devices that allow systems of electronics and sensors to be placed together into very small p ackets of space, making them invaluable as research tools to scientists worldwide. In this wo rk, a specific MEMS device, developed to study thin films of superfluids He and He, is described and studied through computer simul ation using COMSOL. The MEMS device, using comb-shaped el ctrodes and an alternating current to create resonance in the structure, seems to bend aw ay from the electrodes in an unexpected manner when simulated. This could cause problems wh en extrapolating length measurements from capacitance values between electrodes, but it can be accounted for.

In this paper, we report on a concerted modelling effort in the South African water resources sector in which system dynamics provides the paradigmatic framing for both a stakeholder engagement process and for developing an underpinning, integrative simulation model. We describe the design of the parallel modelling approach and examine the progress to date. We highlight the crafting of the engagement sessions to fit the different characteristics and needs of the participating stakeholders and reflect upon outcomes so as to set the project path into the future. In this, we choose to build resilience by a progression from collecting and exploring individual experiences of stakeholders’ problems; to connecting individuals’ experiences to their broader sectors’ problems; and finally to cross-connecting the sectors’ impacts and requirements to one another under different scenarios of change.

A model of the transport system in a copper ore mine was prepared using FlexSim software and the simulations were performed for five days. Empirical parameters were applied to each item of the transport system in order for the ore transport times to correspond to the actual conditions. Both the class-and the loading point-specific haul truck courses were based on the five-day schedule. Mean inter-arrival times were modelled for haul trucks according to empirical histograms. The ore portions were discretized and their masses were based on haul truck load capacities. The simulations were performed for twelve variants covering the unavailability of different ore sources. The recorded statistics include ore provenience, lithology, Cu content and tag survival rate for RFID-tagged ore variants. The model represents the new way of solving the problem of ore mixing in a conveyor beltbased transport system. Adoption of the proposed scheme, will allow the enrichment plant managers to adjust the milling and crushing parameters to the lithology of the ore before it will leave the mine. The model allows to pinpoint the areas in the mine that produce certain demanded lithological factions and helps the managers to choose the most desirable pattern of the mining schedule and forecast the economical outcome.

This paper examines the process of transition to turbulence within an accelerating planar liquid jet. By calculating the propagation and spatial evolution of disturbance wave packets generated at a nozzle where the jet emerges, we are able to estimate break-up lengths and break-up times for different magnitudes of acceleration and different liquid to air density ratios. This study uses a basic jet velocity profile which has shear layers in both the air and the liquid either side of the fluid interface. The shear layers are constructed as functions of velocity which behave in line with our CFD simulations of injecting Diesel jets. The non-dimensional velocity of the jet along the jet centre-line axis is assumed to take the form V (t) = tanh(at) where the parameter a determines the magnitude of the acceleration. We compare the fully unsteady results obtained by solving the unsteady Rayleigh equation, to those of a quasi-steady jet to determine when the unsteady effects are significant, and if the jet can be regarded as quasi-steady in typical operating conditions for Diesel engines.

Urban planning is a complex process as urban system is the resultant of interactions between its subsystems. Knowing future projection of physical urban development can play a vital role in successful urban planning and development. Therefore, it is important to have a good understanding of the interactions between urban system components to correctly predict future urban growth. This paper proposes the Celullar Automata (CA) model to predict the future of urban development. Due to shortcomings of traditional modeling methods which are generally static, linear and are based on simple systems theory, it is expected that the proposed CA model which is dynamic and nonlinear will provide better understanding of the urban system and provide better prediction of urban growth.

Every manufacturing company producing products of any kind is forced to constantly address the issue of improving the efficiency of its production lines, increasing their production capacity and last but not least, increasing the quality of products. Every physical intervention directly in the production process results in a change in the efficiency of this process. It may be a change for the better, but often such a change may not have the expected effect. Today's era of digital industrialization offers us the opportunity to verify possible changes in the production process without physically interfering with existing production, and thus it is also possible to verify the real consequences of the intervention. The present paper deals with improving the efficiency and quality of products in the production process in the food industry. It is the production of various types of packaged salads, cod and other types of fish. The aim of the paper is to test the possibility of improving the efficiency of the packaging line for food products as well as the possibility to improve their quality by applying sensors of foreign bodies of various kinds, which can sometimes get into salads.

This paper presents a study for assessing the dynamic structural deformations of one of the most modern, and portable, measurement equipment: the Coordinate Measuring Arms (CMAs or AACMMs). The study of the measurement errors derived from the use of these instruments is still controversial due to a certain lack of traceability and reliability in measurements due to the influence of the human factor acting on a complex 3D structure (with 6 or 7 degrees-of-freedom). When contact measurements are taken into account, the human factor variable originates non-uniform contact forces, lack of stability, different velocities and accelerations, among unpredictable probing trajectories. All these factors lead to conclude that in every manual measurement involving a CMA there is a structural dynamic deformation caused by the approach movement before probing a contact point as well as by the force exerted during probing. In order to determine the amplitude of this deformation and its distribution along the CMA structure a new methodology has been developed. Both depend on the followed trajectory and on the probing force amplitude and orientation. This work presents the methodology and steps required for the construction of the virtual simulation model. The method employs 3D modelling of all elements of the CMA structure, Finite Element Analysis (FEA) software and multibody simulation techniques with flexible bodies. This set of software tools is nowadays capable of creating dynamic virtual models for the dynamic analysis of complex mechanisms (machines, vehicles…) in optimization tasks. The application of these tools supposes a novel approach to the study of the CMA metrological behaviour.

We present a relatively large-scale initiative in high-quality MT based on semantic transfer, reviewing the motivation for this approach, general architecture and components involved, and preliminary experience from a first round of system integration (to be accompanied by a hands-on system demonstration, if appropriate). The translation problem is one whose solution must be searched incrementally. There will be no dramatic event to signal the end of the search. (Martin Kay, 1982) * Norwegian idiom; literally: 'Like contest-eating with the troll'. According to a traditional Norwegian tale, young Askeladden got engaged in an eating match with a troll, and tricked him by spooning food into a bag he had hidden under his shirt. When the boy eventually cut open the bag, ostensibly to make more room, the ogre imitated him and got killed by his own hand.

In the present work, a method for the analysis of short time intervals in ball bearings is proposed. We study the effect of the internal clearance on the dynamics of ball bearings using recurrence plots and the recurrence quantification approach. In the proposed method, we focused on the analysis of dynamic states generated from the 2-DOF mathematical model, to which a function changing the damping coefficient in the clearance domain was added. Chosen recurrence methods showed the specific dynamic responses by different values of the radial clearance. The effect of self-consistency concerning the damping effect and vibration development is confirmed. The proposed method can be useful for the prediction of variable radial clearance in time by analysis of the acceleration response of ball bearing during its operation.

Just-in-time delivery has become a key aspect of pharmaceutical industry when loyalizing customers and competing internationally. Additionally, prolonged lead times may lead to increased work-inprocess inventory, penalties for non-compliance and cost overrun. The problem is more complex upon considering a wide variety of products as often noted in pharmaceutical companies. It is then relevant to design strategies focusing on improving the delivery performance. Therefore, this paper proposes the use of Discrete-event simulation (DES) to identify inefficiencies and define solutions for the delivery problem. First, input data were gathered and analyzed. Then, a DES model was developed and validated. Finally, potential improvement scenarios were simulated and analyzed regarding productivity rate and proportion of tardy jobs. A case study in a pharmaceutical laboratory is presented to validate the proposed methodology. The results evidenced that, by implementing the best scenario, the productivity may be augmented by 44.83% which would generate zero tardy jobs.

This paper introduces modeling of gravity drainage mechanism, (GD) in Iranian carbonate oil reservoirs. The GD mechanism is an important and active mechanism in fractured carbonate reservoirs through Gas Injection (GI), Water Alternative Gas Injection (WAG) processes ...

How do we consider problems and models in the practice of simulation? It is our possibly contentious observation that simulation model solving seems to be more critical to the mission of simulation modeling than problem solving. Inspired by the theme of this year's Winter Simulation Conference, we ask the question, "Is problem solving, or simulation model solving, mission critical?" To investigate this we look at three perspectives, those of the textbook, the article and the editorial. The textbook perspective is the balance of the "traditional" view of simulation presented by the academic textbook against practical experience. The article perspective is a classification of papers published in four leading simulation journals in the year 2004 (ACM TOMACS, SIMULATION, Simulation Modelling Practice and Theory, and Simulation & Gaming). The editorial perspective is a discussion of editorial policy presented by the same journals. Our findings show that our observation is not contradicted.

How do we consider problems and models in the practice of simulation? It is our possibly contentious observation that simulation model solving seems to be more critical to the mission of simulation modeling than problem solving. Inspired by the theme of this year's Winter Simulation Conference, we ask the question, "Is problem solving, or simulation model solving, mission critical?" To investigate this we look at three perspectives, those of the textbook, the article and the editorial. The textbook perspective is the balance of the "traditional" view of simulation presented by the academic textbook against practical experience. The article perspective is a classification of papers published in four leading simulation journals in the year 2004 (ACM TOMACS, SIMULATION, Simulation Modelling Practice and Theory, and Simulation & Gaming). The editorial perspective is a discussion of editorial policy presented by the same journals. Our findings show that our observation is not contradicted.

A shortage of donor liver grafts unfortunately results in approximately 10% of patients dying whilst listed for a liver transplant in Europe and the United States. Thus it is imperative that all available organs are used as efficiently as possible. This paper reports upon the application of a simulation modelling approach to assess the impact of several alternative allocation policies

This essay gathers some history in addition to memories and information about Douglas-Daly Experiment Station (DDES) in both personal and professional terms. It is only a partial history insofar as it adds to existing information. Perhaps it might be better read as a memoir introduced by some context of my time in the region supplemented by technical summaries of the experimental work that I published in that pre-internet era. The essay may also be seen as my reflection on an influential period in my life, and consequently is subjective despite my best efforts. Writing more than 50 years after my first association with DDES surely renders some memories inaccurate. I am pleased to acknowledge, most gratefully, that my concerns on this front have been reduced after the informative 2023 visit facilitated by Peter Shotten, the long-term manager of the Douglas Daly Research Farm (DDRF) as it is now known.

The complex debate on prehistoric settlement decisions is no longer tackled from a purely archaeological perspective but from a more landscape-oriented manner combined with archaeological evidence. Therefore, reconstruction of several components of the former landscape is needed. Here, we focus on the reconstruction of the groundwater table based on modeling. The depth of the phreatic aquifer influences, for example, soil formation processes and vegetation type. Furthermore, it directly influences settlement by the wetness of a site. Palaeogroundwater modeling of the phreatic aquifer was carried out to produce a series of full-coverage maps of the mean water table depth between 12.7 ka and the middle of the 20th century (1953) in Flanders, Belgium. The research focuses on the reconstruction of the input data and boundary conditions of the model and the model calibration. The model was calibrated for the 1924-1953 time period using drainage class maps. Archaeological site data and podzol occurrence data act as proxies for local drainage conditions over periods in the past. They also served as a control on the simulated phreatic palaeogroundwater levels. Model quality testing on an independent validation data set showed that the model predicts phreatic water table levels at the time of soil mapping well (mean error of 1.8 cm; root mean square error of 65.6 cm). Simulated hydrological conditions were in agreement with the occurrence of archaeological sites of Mesolithic to Roman age at 96% of the validation locations, and also with the occurrence of well-drained podzols at 97% of the validation locations.

The machining industry's evolving environmental consciousness has prompted a growing demand for cutting fluids devoid of chlorine and sulphur, thus fostering sustainable machining practices. This surge in demand is driven by mounting apprehensions over environmental contamination and worker safety. As the industry transitions to modern cutting fluids, it becomes imperative to comprehend their effectiveness and the optimal machine parameters required for their deployment in the turning process. In our current study, we employ the Taguchi technique in conjunction with Grey Relational Analysis (GRA) to assess the efficacy of parameter optimization and its impact on the turning of SS 304 steel, utilizing non-toxic, biodegradable vegetable-based cutting fluids. Our investigation delves into the influence of various process variables, including cooling conditions (CC), cutting speed (Vc), feed rate (f), and depth of cut (a), on critical response parameters like Cutting Force (CF) and Surface Roughness (SR). This is accomplished through rigorous Analysis of Variance (ANOVA) to identify the parameters of significant influence. The study reveals that employing the Minimum Quantity Lubrication (MQL) method at a cutting speed of 1000 revolutions per minute, a feed rate of 90 mm/minute, and a 0.3 depth of cut leads to substantial enhancements in machining performance. The microstructure of the optimized sample is investigated through the use of a Scanning Electron

Bacterial disease is a major cause of suffering and the scarcity of new molecules that can act on bacteria is a major problem. New strategies for developing such molecules might be based on recent concepts in microbiology. Hyperstructures are large assemblies of molecules and macromolecules that perform functions such as DNA replication and chemotaxis and the interactions between hyperstructures have been proposed to constitute an intermediate level of organisation in cells. An entirely new therapy for bacterial diseases might therefore be devised based on the manipulation of hyperstructures. One way to do this would be to supply cells with hybrid metabolites or hybolites made by a pairwise combination of the thousands of small molecules involved in metabolism. Some of these hybolites would be substrates for two, very different, hyperstructures and might do much more than simply inhibit key enzymes and processes within the hyperstructures: they might provoke the assembly of two hyperstructures in the same space or lead to hyperstructures emitting misleading signals. It is conceivable that hybolites might even convert a pathogenic Mr Hyde into an inoffensive Dr Jekyll. The likely action of candidate hybolites on hyperstructure dynamics and hence phenotype might be explored cheaply in silico using stochastic automata such as HSIM.

Changing climate and disturbance regimes are increasingly challenging the resilience of forest ecosystems around the globe. A powerful indicator for the loss of resilience is regeneration failure, that is, the inability of the prevailing tree species to regenerate after disturbance. Regeneration failure can result from the interplay among disturbance changes (e.g., larger and more frequent fires), altered climate conditions (e.g., increased drought), and functional traits (e.g., method of seed dispersal). This complexity makes projections of regeneration failure challenging. Here we applied a novel simulation approach assimilating data‐driven fire projections with vegetation responses from process modeling by means of deep neural networks. We (i) quantified the future probability of regeneration failure; (ii) identified spatial hotspots of regeneration failure; and (iii) assessed how current forest types differ in their ability to regenerate under future climate and fire. We focused...

Discrete Event Simulation (DES) is one of the most effective tools for planning, designing and improving material flows in production. One of the main weaknesses of operating DES is the exertion needed and costs spent on collecting and handling the input data from different organisation's data resources. To tackle the problem of the time consuming input data process for DES projects an Open Source (OS) tool, called Knowledge Extraction (KE) tool was developed. The tool reads data from several organisations' resources; analyses it and outputs it in a format that is applicable to be used by a simulation tool, all conducted in one automated process. The primary, readable to simulation software, output format follows the Core Manufacturing Simulation Data (CMSD). This paper presents the KE tool and a test implementation, as a first step towards the validation of the tool in a real case study in the medical industry.

Discrete Event Simulation (DES) is one of the most effective tools for planning, designing and improving material flows in production. One of the main weaknesses of operating DES is the exertion needed and costs spent on collecting and handling the input data from different organisation's data resources. To tackle the problem of the time consuming input data process for DES projects an Open Source (OS) tool, called Knowledge Extraction (KE) tool was developed. The tool reads data from several organisations' resources; analyses it and outputs it in a format that is applicable to be used by a simulation tool, all conducted in one automated process. The primary, readable to simulation software, output format follows the Core Manufacturing Simulation Data (CMSD). This paper presents the KE tool and a test implementation, as a first step towards the validation of the tool in a real case study in the medical industry.

Planning as Satisfiability is one of the most well-known and effective technique for classical planning: SATPLAN has been the winning system in the deterministic track for optimal planners in the 4th International Planning Competition (IPC) and a co-winner in the 5th IPC. In this paper we extend the Planning as Satisfiability approach in order to handle preferences and SATPLAN in order to solve problems with simple preferences. The resulting system, SATPLAN(P) is competitive with SGPLAN, the winning system in the category "simple preferences" at the last IPC. Further, we show that SATPLAN(P) performances are (almost) always comparable to those of SATPLAN when solving the same problems without preferences: in other words, introducing simple preferences in SATPLAN does not affect its performances. This latter result is due both to the particular mechanism we use in order to incorporate preferences in SAT- PLAN and to the relative low number of soft goals (each corresponding to a simple preference) usually present in planning problems. Indeed, if we consider the issue of determining minimal plans (corresponding to problems with thousands of preferences) the performances of SATPLAN(P) are comparable to those of SATPLAN in many cases, but can be significantly worse when the number of preferences is very high compared to the total number of variables in the problem. Our analysis is conducted considering both qualitative and quantitative preferences, different reductions from quantitative to qualitative ones, and most of the propositional planning domains from the IPCs and that SATPLAN can handle.

Based on the understanding that bearings are critical components of high-speed precision ball-screw systems, the smooth operations of machinery depends on them. There exist several connections that support the roller bearings during operations, most notable are the interfaces between the connecting shaft and bearing and bearing cage support . Contact friction at the connection point or joints is developed between two surfaces in contact regardless of the amount of pressure exacted between them. Consequently, the activities of friction generate heat, which results in a rise in temperature, an event that is detrimental to the structural and material properties of the bearing. The increase in temperature experienced during operation often lead to overheating of the coolant, and the occurrence of mechanical micro-deformations (Reddy, 2015). Hence, the development of high temperature during

The objective of the study was to assess the responsiveness of the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3) to management scenarios that included three rotation lengths (50, 100 and 250 years) under harvest and fire disturbances in six forest types (poplar deep soil, black spruce deep soil, jack pine deep and shallow soils, hardwood mixedwood and other conifer lowland). Outputs from five carbon (C) pools were considered: merchantable stemwood (stump height of 30 cm, minimum DBH of 9 cm and a minimum top diameter of 7 cm), deadwood, soil C, total ecosystem C and cumulative total ecosystem C emissions. Yield curves strongly affected the predicted size of all five pools. Longer rotation lengths led to larger pools with the relative differences between rotation lengths varying with stand types. Pools associated with poplar were usually the largest while those of jack pine on shallow sites were generally the smallest. When compared to the starting point of the simulat...

Context: This paper is developed in the context of Usability Engineering. More specifically, it focuses on the use of modelling and simulation to help decision-making in the scope of usability evaluation. The main goal of this paper is to present UESim: a System Dynamics simulation model to help decisionmaking in the make-up of the usability evaluation team during the process of usability evaluation. To develop this research we followed four main research phases: a) study identification, b) study development, c) running and observation and finally, d) reflexion. In relation with these phases the paper describes the literature revision, the model building and validation, the model simulation and its results and finally the reflexion on it. We developed and validated a model to simulate the usability evaluation process. Through three different simulations we analysed the effects of different compositions of the evaluation team on the outcome of the evaluation. The simulation results show the utility of the model in the decision making of the usability evaluation process by changing the number and expertise of evaluators employed. One of the main advantages of using such a simulation model is that it allows developers to observe the evolution of the key indicators of the evaluation process over time. UESim represents a customisable tool to help decision-making in the management of the usability evaluation process, since it makes it possible to analyse how the key process indicators are affected by the main management options of the Usability Evaluation Process.

This paper presents a wear simulation-based performance evaluation of the conveyor belt transfer chute using the DEM (Discrete Element Method). Compared to known analytical and empirical wear models, DEM simulation can significantly increase the performance of wear analysis by enabling the analysis and optimization of highly complex geometries of material handling systems such as conveyor belt transfer chutes. Only the correct design of the conveyor belt transfer chute has the potential to significantly extend its service life, resulting in considerable cost savings. Based on the parametric analysis of different angles and radius in the upper head and lower section of the transfer chute, a new geometry of the transfer chute was proposed. The wear depth of the new conveyor belt transfer chute is compared with the wear resistant and low-carbon steel of the transfer chute along with the moderate and relatively high values of the solid granules mass flow. The results show that the wear depth of the transfer chute can be significantly reduced by using the wear-resistant steel compared to the low-carbon steel, which is significantly evident in high throughput rates of the solid granules mass flow.

This paper deals primarily with the sedimentation of magnetic microparticles in the presence of an external magnetic field. Based on the analysis of raster images, taken during sedimentation process under the influence of magnetic field, the development of settling velocities occurring as a result of increasing magnetic force is measured. Basics of the magnetic field calculation of a disc neodymium permanent magnet are explained. Numerical particle tracking and particle size determination via image analysis is presented. On the basis of force balance equations for Lagrangian particle tracking and results of experimental tracking of particle positions during sedimentation with magnetic field turned on as well as off, the magnetic susceptibility of microparticles is determined.