The key objective of this research is to develop a generic simulation modelling methodology that can be used to model stochastic continuous systems effectively. The generic methodology renders simulation models that exhibit the following characteristics: short development and maintenance times, user-friendliness, short simulation runtimes, compact size, robustness, accuracy and a single software application. The research was initiated by the shortcomings of a simulation modelling method that is detailed in a Magister dissertation. A system description of a continuous process plant (referred to as the Synthetic Fuel plant) is developed. The decision support role of simulation modelling is considered and the shortcomings of the original method are analysed. The key objective, importance and limitations of the research are also discussed. The characteristics of stochastic continuous systems are identified and a generic methodology that accommodates these characteristics is conceptualised and developed. It consists of the following eight methods and techniques: the variables technique, the iteration time interval evaluation method, the event-driven evaluation method, the Entity-represent-module method, the Fraction-comparison method, the iterative-loop technique, the time “bottleneck” identification technique and the production lost “bottleneck” identification technique. Five high-level simulation model building blocks are developed. The generic methodology is demonstrated and validated by the development and use of two simulation models. The five high-level building blocks are used to construct identical simulation models of the Synthetic Fuel plant in two different simulation software packages, namely: Arena and Simul8. An iteration time interval and minimum sufficient sample sizes are determined and the simulation models are verified, validated, enhanced and compared. The simulation models are used to evaluate two alternative scenarios. The results of the scenarios are compared and conclusions are presented. The factors that motivated the research, the process that was followed and the generic methodology are summarised. The original method and the generic methodology are compared and the strengths and weaknesses of the generic methodology are discussed. The contribution to knowledge is explained and future developments are proposed. The possible range of application and different usage perspectives are presented. To conclude, the lessons learnt and reinforced are considered. / Thesis (PhD (Industrial Engineering))--University of Pretoria, 2004. / Industrial and Systems Engineering / unrestricted

Bostadsmarknaden är en marknad i ständig förändring. Flera faktorer såsom populationstillväxt, bostadsideal och kriser påverkar planerandet och genomförandet av nya bostäder och dess utveckling.I samhällelig förändring, utveckling och planering är bostadsmarknaden en stor del. I en fungerande samhällsplanering krävs det att det planeras för hur dagens, och framförallt morgondagens bostäder ska se ut efter människans behov, ideal och ekonomiska möjligheter.  Denna studie undersöker hur bostadsmarknaden har påverkats av en händelsebaserad kris – Covid-19. Teorier och tidigare forskning har tagits i beaktning för att kunna genomföra denna studie på ett trovärdigt vis. Det resonerades fram till att detta ämne skulle undersökas eftersom bostadsmarknaden är en stor del av den generella samhällsplaneringen, samt ett ständigt aktuellt ämne. Om nu mer aktuellt än någonsin tidigare. Syftet med studien är därigenom att konkretisera för hur bostadsmarknaden och planeringen av den har förändrats av en händelsebaserad kris; med utgångspunkt i Covid-19. För att undersöka detta har tre frågeställningar formulerats.  Studiens frågeställningar är följande.       Hur har bostadsmarknaden i Sveriges städer och tätorter utvecklats under Covid-19? Har invånarna i Sveriges bostadsideal sett till geografiskt läge och funktion förändrats under Covid-19? Vilka begränsningar/möjligheter har Covid-19 lett till vad gäller planerandet och genomförandet av nyproduktioner i Sveriges städer med utgångspunkt i Karlstad?  Undersökningen har kunnat genomföras utifrån tidigare forskning och en kombinerad metod. En kombinerad metod som tillvägagångssätt innebär att det både har använts kvalitativa och kvantitativa metoder för att nå studiens resultat. Den kvalitativa intervjun genomfördes för att kunna ta del av en djupare analys om hur bostadsmarknaden har förändrats under denna period. Intervjupersonen är verksam inom fastighetsbranschen och har erhållit lång erfarenhet. Den kvantitativa forskningen gjordes för att kunna få en bild av bostadsmarknadens utveckling sett över hela landet, i både storstad och mindre tätort. De tillfrågade respondenterna i den kvantitativa forskningen var alla fastighetsmäklare eller fastighetsmäklarassistenter.  Slutsatsen av studien är att bostadsmarknaden till stor del har påverkats av Covid-19 och att bostadens roll för människan har blivit allt mer central. / The real estate market is a market in constant change. Several factors such as population growth, housing ideals and crises affect the planning and implementation of new housing and its development. In social change, development and planning, the real estate market is a large part. In a functioning community planning, it is required that it is planned for how today's and especially tomorrow's homes will look according to human needs, ideals and economic opportunities. This study examines how the real estate market has been affected by an event-driven crisis - Covid-19. Theories and previous research have been taken into account in order to carry out this study in a credible way. It was concluded that this topic should be investigated because the real estate market is a constantly current topic, if now more relevant than ever before. Also, because the real estate market is a large part of the general urban planning. The purpose of the study is there for to concretize how the real estate market and the planning of it have been affected by an event-driven crisis with a starting point in Covid-19. Three following issues have been phrased to examine this topic. The issues of this study are the following.   How has the real estate market in Sweden's cities and towns developed during Covid-19?  Have the inhabitants of Sweden's housing ideal in terms of geographical location and function changed during Covid-19?  What limitations/opportunities has Covid-19 led to in terms of planning and implementation regarding new productions in Sweden with an outset in Karlstad?  The survey has been able to be carried out based on previous research and a combined method. A combined method as an approach means that both qualitative and quantitative approaches have been used to achieve the results of the study. The qualitative interview was conducted to get a deeper analysis of how the real estate market has changed during this period. The interviewee is active in the real estate industry and has years of experience. The quantitative research was done to be able to get a bigger picture of the development of the real estate market across the country, in both large cities and smaller towns. The respondents surveyed in the quantitative research were all real estate agents or real estate assistants. The conclusion of the study is that the real estate market has been affected by Covid-19 in large term and that the home has become increasingly more central in human life.

[pt] Nesse trabalho comparamos o uso da programação reativa estruturada com o uso do ReactiveX no desenvolvimento de aplicações reativas soft real time. Apresentamos implementações de aplicações em Lua que demonstram o uso desses modelos em diferentes situações, destacando as vantagens de cada um. Consideramos também o seu uso combinado em uma mesma aplicação. Além disso, implementamos um módulo que permite utilizar a programação reativa estruturada em Lua e utilizamos o módulo RxLua que implementa o modelo ReactiveX. / [en] In this work we compare the use of structured reactive programming and ReactiveX in the development of reactive soft real time applications. We present application implementations using Lua that demonstrate the use of these models in multiple situations, pointing the advantages of using each one. Another consideration is combining both models in a single application. We also developed a module that allows the use of structured reactive programming in Lua and used the RxLua module which implements the ReactiveX model.

No description available.

Particulate systems in practical applications such as biomass combustion, blood cellular systems and granular particles in fluidized beds, have often been computationally represented using spherical surfaces, even though the majority of particles in archetypal fluid-solid systems are non-spherical. While spherical particles are more cost-effective to simulate, notable deficiencies of these implementations are their substantial inaccuracies in predicting the dynamics of particle mixtures. Alternatively, modeling dense fluid-particulate systems using non-spherical particles involves increased complexity, with computational cost manifesting as the biggest bottleneck. However, with recent advancements in computer hardware, simulations of three-dimensional particulate systems using irregular shaped particles have garnered significant interest. In this research, a novel Discrete Element Method (DEM) model that incorporates geometry definition, collision detection, and post-collision kinematics has been developed to accurately simulate non-spherical particulate systems. Superellipsoids, which account for 80% of particles commonly found in nature, are used to represent non-spherical shapes. Collisions between these particles are processed using a distance function computation carried out with respect to their surfaces. An event - driven model and a time-driven model have been employed in the current framework to resolve collisions. The collision model's influence on non–spherical particle dynamics is verified by observing the conservation of momentum and total kinetic energy. Furthermore, the non-spherical DEM model is coupled with an in-house fluid flow solver (GenIDLEST). The combined CFD-DEM model's results are validated by comparing to experimental measurements in a fluidized bed. The parallel scalability of the non-spherical DEM model is evaluated in terms of its efficiency and speedup. Major factors affecting wall clock time of simulations are analyzed and an estimate of the model's dependency on these factors is documented. The developed framework allows for a wide range of particle geometries to be simulated in GenIDLEST. / Master of Science / CFD – DEM (Discrete Element Method) is a technique of coupling fluid flow solvers with granular solid particles. CFD – DEM simulations are beneficial in recreating pragmatic applications such as blood cellular flows, fluidized beds and pharmaceutics. Up until recently, particles in these flows have been modeled as spheres as the generation of particle geometry and collision detection algorithms are straightforward. However, in real – life occurrences, most particles are irregular in shape, and approximating them as spheres in computational works leads to a substantial loss of accuracy. On the other hand, non – spherical particles are more complex to generate. When these particles are in motion, they collide and exhibit complex trajectories. Majority of the wall clock time is spent in resolving collisions between these non – spherical particles. Hence, generic algorithms to detect and resolve collisions have to be incorporated. This primary focus of this research work is to develop collision detection and resolution algorithms for non – spherical particles. Collisions are detected using inherent geometrical properties of the class of particles used. Two popular models (event-driven and time-driven) are implemented and utilized to update the trajectories of particles. These models are coupled with an in – house fluid solver (GenIDLEST) and the functioning of the DEM model is validated with experimental results from previous research works. Also, since the computational effort required is higher in the case of non – spherical particulate simulations, an estimate of the scalability of the problem and factors influencing time to simulations are presented.

Cette thèse s'est déroulée dans le cadre du projet SECMAR qui visait à sécuriser le Grand Port Maritime de Marseille. Notre objectif était d'aider les personnels du port à identifier les comportements menaçant des navires afin de pouvoir agir efficacement en cas de danger réel. A ce titre, nous avons développé un système d'analyse et de reconnaissance de comportements de navires formé de deux sous-modules complémentaires. Le premier est construit à partir de l'approche probabiliste Modèle de Markov Cachée et traite principalement des comportements nominaux des gros bateaux qui se caractérisent par un déplacement régulier et récurrent dans le port. Le second est construit à partir du langage réactif synchrone Esterel et prend en compte les comportements agressifs et transgressifs de tous types de navires, notamment ceux des petits bateaux qui circulent librement et aléatoirement dans le port. Le système global d'aide à la décision a permis une bonne reconnaissance en temps-réel des différents comportements de navires au cours de leurs évolutions dans le port. Au regard des résultats prometteurs que nous avons obtenu à travers ce module, il est envisageable de le généraliser à d'autres ports mondiaux ainsi qu'à d'autres domaines d'application, notamment le domaine aéroportuaire. / The overall aim of this thesis was to create a decision support system that identifies discrepancies in ship behavior. The thesis was a part of the SECMAR project that aimed to improve security at the Marseilles harbor by the creation of decision support system for port staff. For this purpose, we developed a recognition behavior system consisting of two complementary sub-systems.The first system was based on the probabilistic Hidden Markov model approach and deals with nominal behavior of large to medium size commercial ships showing regular and recurrent behavior. The second system was based on the reactive synchronous language Esterel and concerns aggressive and transgressive behavior of small ships that may navigate freely in the harbor. Real-time evaluations showed that the proposed decision support system efficiently captured and evaluated ship behaviors. The promising results of the system and its diversity in origin makes it suitable for applications in other harbors as well as other environment such as airports.

服務導向架構(Service-Oriented-Architecture, SOA)與事件導向架構(Event-driven Architecture, EDA)的結合應用將成為未來Real-Time Enterprise軟體應用系統架構的主流趨勢，雖然兩架構的結合可以整體提升應用系統之反應、整合與溝通的能力，但若無良好的事件管理機制及搭配提供服務的配套設計，則難以充分發揮兩架構結合的互補綜效。本研究所提出之調適式SOA有效事件模型，以事件價值觀點(Value-driven)分析事件所提供的價值對使用者的重要性與效益。由於使用者所重視的事件價值不同，因此也為各別使用者設計一調適性事件語意資訊模型(Customized Event Ontology Model)，作為篩選事件的依據，另外，事件管理機制也可運用智慧型代理人(Agent)觀察使用者採用事件的行為，透過學習更新事件過濾的規則，並可建議使用者取消訂閱(subscribe)不重視的事件。本研究同時搭配設計一事件與服務對應的機制，並透過此機制連結外部環境所提供的服務。本研究所提出之調適式SOA有效事件模型，預期可提供更為健全的服務導向架構(SOA)與事件導向架構(EDA)的結合應用設計，讓使用者可以真正受惠於此種應用軟體架構結合的好處與效用。 / The combination of Service-Oriented-Architecture (SOA) and Event-driven Architecture (EDA) will become the main trend of application architecture of Real-Time Enterprise in the future. Although the combination of these two architectures can enhance an application system’s capabilities in response, integration and communication as a whole, it’s hardly to extend these two architectures’ complemented advantages unless there is a sound mechanism for advanced event and service management. This paper presents a novel methodology which can analyze the importance and impacts of events’ values to users. Based on different emphases on events’ values among users, this research can also develop a Customized Event Ontology Model used as the basis for filtering events for an individual user. The event management mechanism designs an intelligent agent in order to observe the records of a user’s history events and to learn new filtering rules of events. The mechanism can also suggest the user to cancelling events which are insignificant to him. Furthermore, this study devises a mechanism to bridge the connections between events and services. The contribution of my methodology aims to provide an advanced solution of combining the architectures of SOA and EDA in order for a user to exert up-to-date information for personalized competitive advantage.

No description available.

Cette thèse a pour objet l'étude expérimentale et numérique de l'écoulement de particules dans un empilement de sphères plus grosses. <br />Un dispositif expérimental a été mis au point pour étudier la dispersion latérale et le temps moyen de séjour d'un paquet de particules dans un milieu poreux. Nous avons en particulier déterminé la dépendance du temps moyen de transit en fonction du nombre de particules en écoulement, de la taille des particules et de la hauteur du milieu poreux. Nous avons également caractérisé la dépendance du coefficient de dispersion latéral vis-à-vis du nombre de particules transitant dans la structure poreuse.<br />Dans un deuxième temps, nous avons développé des modèles de simulations numériques basés sur les méthodes "Event-Driven" et "dynamique moléculaire de sphères molles". Ceux-ci nous ont permis de compléter l'étude expérimentale en analysant l'influence de divers paramètres supplémentaires. L'accès à l'intérieur du milieu poreux a permis une analyse plus fine de la dispersion des particules. <br />Enfin, nous avons abordé la possibilité d'utiliser le phénomène de percolation spontanée pour réaliser un mélangeur. Grâce à l'outil numérique, nous avons réalisé et caractérisé des mélanges de particules de tailles différentes. Nous avons alors montré que ce procédé s'avère être un moyen simple et efficace pour obtenir des mélanges homogènes de particules.

本研究遵循模型驅動架構的概&#63907;，發展一適用於現實商業&#63946;程之工作&#63946;程模型，採用創新的方式對於工作&#63946;程做描述，我們只需要按照固定的步驟，&#63845;可以將真實的商業&#63946;程發展成可用的模型，以&#63965;於後續發展工作&#63946;程系統之用。在發展模型時，我們採用&#63930;IBM的資訊框架（IFW）做為塑模的方式，以及&#63965;用統一塑模語言中的&#63994;態移轉圖和循序圖的概&#63907;&#63789;做為呈現工作&#63946;程模型，解決&#63930;傳統&#63946;程無法表達&#63946;程內部資&#63934;變化所帶&#63789;的影響，除此之外，我們在模型發展後，採用包含事件-驅動概&#63907;的工作&#63946;程引擎&#63789;產生工作&#63946;程系統，我們將商業&#63946;程視為一個個的物件，物件收發事件導致&#63994;態的改變而引發另一個事件的發生，如此循環下去，直到整個&#63946;程完成。