The natural phenomena simulation in computer graphics is commonly achieved by the procedural methods or the physics model. However, these approaches are hard to directly approach the visual experience. On the other hand, the image reconstruction works can provide the outcome based on real images but lack of interactivity and efficiency on using image resource. For solving these drawbacks, we propose a novel method that enhances the fire simulation effect using the visual learning of image features and generates continuous animations by integrating with procedural methods. We first obtain the dynamics of fire contour by binarization and edge detection. The information extracted from images is gathered into a set of feature data called fire profile. To generate a long sequence of fire animation from a short clip of fire video, we propose two approaches of visual learning to utilize fire profile to produce continuous animation. One is to use the fire image to setup a color value lookup table which contains the average color value of the fire spatial divisions; the other is to design a state machine for describing fire wiggling movement that can generate effects based on user¡¦s input. During the rendering stage of 3D visualization, we set up the fire volume which connecting the feature points of two cross-views by the cubic spline. Then the edge points found on the fire volume can be used as the contour points of the supplementing slices and generate these supplements inside the planned fire volume to formulate a complete fire effect. The proposed method can raise not only the visual reality but also the interactive ability compared with the existing work.

This thesis studies the following four topics by CFD simulation. First, the detailed airflow patterns and pressure characteristics of a semiconductor fab were analyzed and verified by available experimental data. Second, both transient and steady state simulations of a fire incidence were conducted to study the influences of fire source volume, fire source altitude, and clean room filter face velocity on the temperature distribution around the vicinity of fire source. Note the temperature distribution at the altitude of fire distinguisher (close to the height of ceiling) is very related to the action mechanism of fire distinguisher. Third, the mean trajectories of various particle sizes in the very early stage of a fire occurrence were simulated to provide substantial information to properly locate the VESADs (very early smoke detect active). Fourth, the performances of three commonly adopted smoke control/exhaust systems for semiconductor fabs were evaluated. An appropriate smoke control/exhaust system is provided and discussed.

The work presented in this thesis focuses on the problem of reconstructing threedimensional models of fire from real images. The intended application of the reconstructions is for use in research into the phenomenon of fire-induced high voltage flashover, which, while a common problem, is not fully understood. As such the reconstruction must estimate not only the geometry of the flame but also the internal density structure, using only a set of a few synchronised images. Current flame reconstruction techniques are investigated, revealing that relatively little work has been done on the subject, and that most techniques follow either an exclusively geometric or tomographic direction. A novel method, termed the 3D Fuzzy Hull method, is proposed, incorporating aspects of tomography, statistical image segmentation and traditional object reconstruction techniques. By using physically based principles the flame images are related to the relative flame density, allowing the problem to be tackled from a tomographic perspective. A variation of algebraic tomography is then used to estimate the internal density field of the flame. This is done within a geometric framework by integrating the fuzzy c-means image segmentation technique and the visual hull concept into the process. Results are presented using synthetic and real flame image sets. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, 2007.

After fire is discovered in an underground coal mine, a decision must be made to mitigate fire consequences. The decision should be made based on existing conditions, with the goal of increasing the probability of fire extinguishing without compromising the health and safety of the firefighting personnel. However, the determination of fire conditions can be difficult due to coarse in-situ measurements, fire hazards, and the large domains of interest. Additionally, CFD and network models used for predicting fire conditions are computationally expensive with long simulation processing times for informing real-time decision making. A new generalized procedure to design artificial neural networks (ANNs) capable of making predictions of fire conditions, performing hazard/risk assessment, and providing useful information to the firefighters is presented and applied to different underground coal mine fire scenarios. The feed-forward ANNs were developed to classify fires so as to provide the best firefighting decision and determine useful information in real time, such as response time and fire size. The networks were trained to make predictions on different mine locations and to use only available and measurable information in underground coal mines as inputs. The data used for training and testing the networks was generated using high-fidelity CFD and network fire simulations. Additionally, this research presents the applicability of optical fiber sensing technology for continuous, distributed, and real-time sensing. This new technology could be used for collection of input parameters during ongoing fires, leading to improvement of the prediction performance of the ANNs developed. Finally, a new approach to simulate firefighting foam flow through gob areas is proposed and tested using experimental results obtained from a scaled down experimental setup. / Doctor of Philosophy / Mine fires still represent a serious hazard in underground coal mines. The MSHA incident database shows that around 600 mine fire incidents and 33 fatalities were reported in the U.S. during the last two decades. Most fatalities and injuries that occurred in the aforementioned incidents can be attributed to lack of knowledge on existing fire conditions, leading to poor subjective decisions during fire response. Unfortunately, the in-situ determination or prediction of fire conditions are not easy tasks due to fire hazards, mine entries extensions, and simulation processing times. For this reason, this work presents new data-driven models capable of predicting and evaluating fire conditions. Its goal is to recommend the most suitable firefighting decision, as well as determine fire characteristics and response time to increase the probability of fire extinguishing without compromising mine personnel health and safety. These data-driven models are composed of artificial neural networks (ANNs), allowing for performing predictions in real time and using only available information in underground coal mines. The data used for training and testing these ANNs was generated from fire simulations. Additionally, this research proposes a new technology, such as optical fiber sensing for continuous, distributed, and real time sensing. Optical fiber sensing could contribute with more precise ANNs inputs collection, leading to a better performance prediction. Finally, an alternative way to simulate firefighting foam through gob areas for fire mitigation was proposed and tested using results obtained from experiments. This work represents a significant advancement in underground coal mine fire characterization and response.

Simulating fire propagation in games can be problematic since it requires immense computational power if the fire is portrayed physically accurate. To decrease the computational power required, simplifications and approximations must be made. The aim of this thesis is to evaluate possible methods for simulating fire spread in a networked game environment. More specifically, a level set and a node graph method are implemented and investigated. A vector field was created with the different level properties, which the two methods used as a base for the fire behavior. The performance and overall behavior of the methods were evaluated and tested in order to create an optimized simulation suited for games. Two implementations were made in the Frostbite game engine. The level set propagates the fire with two different level set operators; the normal advection operator and the vector field operator. The normal advection operator spreads the fire outwards in the normal direction. The vector field operator spreads the fire front according to the vector field. The node graph implementation uses a semi-connected bi-directed graph with nodes as starting positions for the fire. The fire spreads through the nodes via their connections. This implementation also depends on the vector field which was translated to the nodes through scalar projection. The vector field represents the properties of fire dynamics and can be adjusted to move the level set and node graph implementation according to wind, slope and fuel. The node graph implementation was further developed with networked capabilities, a heat grid which translates the heat of the node graph making it possible to sample the heat at a position within the level, and also basic interaction with vegetation. / <p>Examensarbetet är utfört vid Institutionen för teknik och naturvetenskap (ITN) vid Tekniska fakulteten, Linköpings universitet</p>

L’évaluation de performance de modèles est une étape fondamentale de leur développement et amélioration. Le travail de recherche présenté dans ce manuscrit est consacré l’évaluation des modèles de propagation des incendies des forêts. Une revue des travaux a montré que si de nombreux éléments étaient disponibles, aucune solution normalisée et automatisable était proposée dans ce champ applicatif. Une solution à ce problème est proposée en déclinant une approche formelle développée dans le cadre de la théorie de la modélisation et simulation. Cette étape a permis de déterminer conceptuellement quels composants devaient être développés et comment les interconnecter.La réalisation de ce cadre a requis premièrement la normalisation de données disponibles pour les incendies de forêts, aucun standard de fichier ou même nomenclature n’étant disponible et/ou utilisé par les modélisateurs ou ingénieurs (observations ou simulation). Un ensemble de nom, notation et format d’encodage des données dans un conteneur NetCDF a pour cela été proposée. Une seconde étape a consisté à déterminer les métriques nécessaires à quantifier les erreurs de simulation (score de simulation). Si quatre méthodes standard ont pu être identifiées dans la littérature, nous avons pu montrer qu’elles se limitaient à la comparaison à un instant donné, ne pouvant donc rendre compte de la performance de la dynamique d’une simulation incendie. Cette problématique a été traitée en proposant deux nouvelles méthodes de calcul de score spécifiques. Ces différentes méthodes d’évaluations ont étés implantées au sein d’une bibliothèque de calcul. Enfin la réalisation d’une évaluation de modèles a été réalisée à l’aide d’une implantation du cadre définit précédemment. Cette évaluation a consisté à confronter quatre formulations de modèles de vitesse de front de flammes effectué sur 80 simulations d’incendies réels de manière complètement automatique. L’automatisation, et le non ajustement de paramètres, a ainsi permis de se rapprocher au plus près du contexte opérationnel où peu d’information locale est disponible, peu de temps après l’alerte de l’éclosion d’un incendie. Les résultats ont démontrés que cette approche est de nature à laisser apparaître une hiérarchie des performances de paramétrisations ou formulation relativement à une autre, sans toutefois être en mesure de donner une mesure absolue et objective de l’erreur modèle. / Performance evaluation of models is a fundamental step towards an efficient development and improvement. The research work presented in this manuscript is devoted to the evaluation of forest fire simulation models. Review of current work showed that if many elements were available, there were not any standardized and automated solutions proposed in this field. A solution for this problem is thus proposed, built upon a formal approach from the theory of modelling and simulation. This formal framework allowed to identify conceptually which components should be developed and how they would be interconnected.Realization of this frame required to start with a normalization of available wildfires data, as no standardized file or even nomenclature were available and/or used by all modellers and engineers (observations or simulation). A set of standard notation and name as well as a standard encoding data format in a scientific container NetCDF is proposed along with associated software.A second step is devoted to the identification of the scoring methods required to quantify the simulation error. If four standard methods have been defined in the literature, we have shown that these methods were limited for the comparison at specific time, not reporting clearly the performance of the simulation dynamics. This issue has been solved by proposing two new specific score calculation. These different evaluations methods are implanted in an open source computation library.Eventually, the realization of models evaluation was performed using an implementation of the proposed experimental frame. This evaluation consisted to confront four formulations of flame front velocity models on 80 real wildfire simulations in a fully automatic way. Because it was automatic, it implied that no parameters adjustments could be performed by an operator after the fire was observed; being more representative of an operational context with little information available immediately after a fire has been reported.The results have shown that this approach, while unable to provide an absolute measure of the model error is capable to reveal a hierarchy of performances between parameterizations or formulations.

The direct exposure to fire is not the most immediate threat to passengers&amp / #8217 / life in case of fire in an underground transportation system. Most of the casualties in fire are the results of smoke-inhalation. Numerical simulation of fire and smoke propagation provides a useful tool when assessing the consequence and deciding the best evacuation strategy in case of a train fire inside the underground transportation system. In a station fire the emergency ventilation system must be capable of removing the heat, smoke and toxic products of combustion from the evacuation routes to ensure safe egress from the underground transportation system station to a safe location. In recent years Computational Fluid Dynamics has been used as a tool to evaluate the performance of emergency ventilation systems. In this thesis, Computational Fluid Dynamics technique is used to simulate a fire incidence in underground transportation systems station. Several case studies are performed in two different stations in order to determine the safest evacuation scenario in CFDesign 7.0. CFD simulations utilize three dimensional models of the station in order to achieve a more realistic representation of the flow physics within the complex geometry. The steady state and transient analyses are performed within a simulation of a train fire in the subway station. A fire is represented as a source of smoke and energy. In transient analyses, a fast t2 growth curve is used for the heat release rate and smoke release rate. The results of the studies are given as contour plots of temperature, velocity and smoke concentration distributions. One of the case studies is compared with a code well known in the discipline, the Fire Dynamics Simulator, specifically developed for fire simulation. In selection of the preferred direction of evacuation, fundamental principles taken into consideration are stated.

Over the past century, great strides have been made in the advancement of mine fire knowledge since the 1909 Cherry Mine Fire Disaster, one of the worst in U.S. history. However, fire hazards remain omnipresent in underground coal mines in the U.S. and around the world. A precise fire numerical analysis (simulation) before any fire events can give a broad view of the emergency scenarios, leading to improved emergency response, and better health and safety outcomes. However, the simulation cost of precise large complex dynamical systems such as fire in underground mines makes practical and even theoretical application challenging. This work details a novel methodology to reduce fire and airflow simulation costs in order to make simulation of complex systems around fire and mine ventilation systems viable. This study will examine the development of a Reduced Order Model (ROM) to predict the flow field of an underground mine geometry using proper orthogonal decomposition (POD) to reduce the airflow simulation cost in a nonlinear model. ROM proves to be an effective tool for approximating several possible solutions near a known solution, resulting in significant time savings over calculating full solutions and suitable for ensemble calculations. In addition, a novel iterative methodology was developed based on the physics of the fluid structure, turbulent kinetic energy (TKE) of the dynamical system, and the vortex dynamics to determine the interface boundary in multiscale (3D-1D) fire simulations of underground space environments. The proposed methodology was demonstrated to be a useful technique for the determination of near and far fire fields, and could be applied across a broad range of flow simulations and mine geometries. Moreover, this research develops a methodology to analyze the tenable limits in a methane fire event in an underground coal mine for bare-faced miners, mine rescue teams, and fire brigade teams in order to improve safety and training of personnel trained to fight fires. The outcomes of this research are specific to mining although the methods outlined might have broader impacts on the other fields such as tunneling and underground spaces technology, HVAC, and fire protection engineering industries. / Ph. D.

The diploma thesis deals with smoke and heat ventilation systems in underground car parks. In the theoretical part of the thesis, legislative and standard background is described. The theoretical part also contains description of fire dynamics simulation methods and effect of carbon monoxide on human health. The practical part includes the design of service, smoke and heat ventilation systems in the selected building. Functionality of particular design is verified by FDS simulations.

Die Digitalisierung im Bauwesen schreitet immer weiter voran und während in diesem Zusammenhang oftmals das Stichwort Building Information Modeling (BIM) fällt, entwickeln sich Disziplinen wie das Brandschutzingenieurwesen (BSI) unabhängig weiter. Das Brandschutzbüro Brandschutz Consult Ingenieurgesellschaft mbH Leipzig (BCL) verwendet das BSI, um ingenieurtechnische Verfahren heranzuziehen. BCL verfolgt als Unternehmensphilosophie das Ziel, mit neuen Methoden und Erkenntnissen ständig die eigenen Prozesse zu optimieren und zu erweitern. Unter diesem Gesichtspunkt soll in dieser Arbeit in Kooperation mit BCL untersucht werden, inwieweit sich die Ergebnisse aus einer Brandsimulation, darunter besonders der Rauch, in einer virtuellen Realität (engl. Virtual Reality (VR)) darstellen und in bestehende oder potenzielle Anwendungsfälle integrieren lassen. Dazu soll zunächst mit einer Betrachtung der brandschutztechnischen Grundlagen inklusive des BSIs und einer Analyse zum Stand des Brandschutzes in BIM begonnen werden. Im nächsten Schritt sind für die Brandsimulation bestimmte Fragen zu klären, wie z.B. eine entsprechende Berechnung technisch abläuft und welche Ausgabedaten und -formate eine solche Simulation bereitstellt. Zur Darstellung der Simulationsergebnisse in virtuellen Realitäten werden Grafik.Engines benötigt, die VR-Anwendungen ermöglichen. Wichtige Untersuchungsgegenstände sind z.B. die anwendbaren Programmier- und Skriptsprachen, mit deren Einsatz die Daten eingelesen und visualisiert werden können. Für die gefundenen Grafik-Engines wird dann recherchiert, ob es bereits bestehende Anwendungen oder Prozesse zur Darstellung von Brandsimulationen gibt. Ist dies der Fall, sollen deren Workflows untersucht werden, um anschließend ihre grundsätzliche Einsatzfähigkeit zu bewerten und Verbesserungsvorschläge zu äußern...:1. Prozesse im Brandschutz 1.1. Brandschutztechnische Grundlagen 1.2. Angewandte Ingenieurmethoden 1.3. Brandschutz mit Building Information Modeling 2. Ablauf einer Brandsimulation 2.1. Verfügbare Software 2.2. Aufbau einer FDS-Eingabedatei 2.3. Generieren von Simulationsdaten in FDS 2.4. Ausgabedaten und -formate 3. Software zur Darstellung in VR 3.1. Blender 3.2. Unity Engine 3.3. Unreal Engine 3.4. Vergleich der Engines 4. Visualisierung der Brandsimulation 4.1. Konzept der Datenübertragung 4.2. Bestehende Workflows für VR-Programme 4.3. Versuchsdurchführung 4.4. Auswertung der Versuche 5. Anwendungsfälle und Optimierungspotenzial 5.1. Potenzielle Einsatzmöglichkeiten 5.2. Optimierungspotenzial 6. Fazit A. Beispielmodell Blender B. Beispielmodell VRSmokeVis C. Prüfmodell Abkürzungsverzeichnis Abbildungsverzeichnis Tabellenverzeichnis Literaturverzeichnis / Digitization in the construction industry is progressing and while the keyword Building Information Modeling (BIM) is frequently mentioned, disciplines like the fire safety engineering are also evolving independently. The fire protection office Brandschutz Consult Ingenieurgesellschaft mbH Leipzig (BCL)) uses fire safety engineering for including engineering procedures. As a corporate philosophy BCL pursues the goal of constantly optimizing and expanding its own processes with new methods and scientific findings. From this point of view, in cooperation with BCL, this master thesis will examine to which extent it is possible to visualize the results of a fire simulation, in particular including the smoke, in Virtual Reality (VR) and to integrate them into existing or evolving applications. For this purpose, a consideration of the fire protection basics including fire protection engineering and an analysis of the status of fire protection in BIM has been started. In the next step the fire simulation must be investigated, i.e. how the corresponding calculation technically works and which output data and formats such a simulation provides. Graphic engines that enable VR applications are required to display the simulation results in VR. Important objects of investigation are e.g. the applicable programming and scripting languages. Those scripting languages are used to import and visualize the data. For the graphic engines found, research is initiated to determine whether there are already existing applications or processes for displaying fire simulations. If this is the case these workflows should be examined in order to subsequently evaluate their fundamental usability and to express suggestions for improvement. If possible, some of the optimizations should be carried out. Based on the existing processes in fire protection helpful application options are derived, for which the use must be proven in future projects.:1. Prozesse im Brandschutz 1.1. Brandschutztechnische Grundlagen 1.2. Angewandte Ingenieurmethoden 1.3. Brandschutz mit Building Information Modeling 2. Ablauf einer Brandsimulation 2.1. Verfügbare Software 2.2. Aufbau einer FDS-Eingabedatei 2.3. Generieren von Simulationsdaten in FDS 2.4. Ausgabedaten und -formate 3. Software zur Darstellung in VR 3.1. Blender 3.2. Unity Engine 3.3. Unreal Engine 3.4. Vergleich der Engines 4. Visualisierung der Brandsimulation 4.1. Konzept der Datenübertragung 4.2. Bestehende Workflows für VR-Programme 4.3. Versuchsdurchführung 4.4. Auswertung der Versuche 5. Anwendungsfälle und Optimierungspotenzial 5.1. Potenzielle Einsatzmöglichkeiten 5.2. Optimierungspotenzial 6. Fazit A. Beispielmodell Blender B. Beispielmodell VRSmokeVis C. Prüfmodell Abkürzungsverzeichnis Abbildungsverzeichnis Tabellenverzeichnis Literaturverzeichnis