"In the prediction of phenomenon behavior there is a presupposition that a similarity exists between model and phenomenon. Success of application is derived from that similarity. An example of this approach is the use of similarity conditions such as Reynolds number in flow problems or Fourier number in heat transfer problems. The advent of performance-based codes has opened up opportunities for many diverse avenues of fire model implementation. The reliability of models depends upon model correspondence uncertainty. Model correspondence uncertainty is incomplete and distorted information introduced into a simulation by a modeling scheme. It manifests itself as 1) the uncertainty associated with the mathematical relationships hypothesized for a particular model, and 2) the uncertainty of the predictions obtained from the model. Improving model implementation by providing a method for rank-ordering models is the goal of the Model Validity Criterion (MVC) method. MVC values can be useful as a tool to objectively and quantitatively choose a model for an application or as part of a model improvement program. The MVC method calculates the amount of model correspondence uncertainty introduced by a modeling scheme. Model choice is based upon the strategy of minimizing correspondence uncertainty and therefore provides the model that best corresponds to the phenomenon. The MVC value for a model is quantified as the sum of the length of two files. These files are individual measures of model structure correspondence uncertainty and model behavior correspondence uncertainty. The combination of the two uncertainty components gives an objective and structured evaluation of the relative validity of each model from a set of likely candidate models. The model with the smallest uncertainty files has the lowest MVC value and is the model with the most validity. Ultimately the value of such a method is only realized from its utility. Example applications of the MVC method are demonstrated. Examples evaluate the rank-ordering of plume physics options used within the computer zone model WPI-Fire when validated against upper layer temperature data from compartment-fire test scenarios. The results show how candidate models of a set may be discriminated against based on validity. These results are powerful in that they allow the user to establish a quantitative measure for level of model performance and/or choose the most valid model for an application."

Past decades of auditory research have identified several acoustic features that influence perceptual organization of sound, in particular, the frequency of tones and the rate of presentation. One class of stimuli that have been intensively studied are sequences of tones that alternate in frequency. They are typically presented in patterns of repeating doublets ABAB… or repeating triplets ABA-ABA-... where the symbol “-” stands for a gap of silence between triplets repeats. The duration of each tone or silence is typically tens to hundreds of milliseconds, and listeners hearing the sequence perceive either one auditory object ("stream integration") or two separate auditory objects (“stream segregation”). Animal studies have characterized single- and multi- unit neural activity and event-related local field potentials while systematically varying frequency separation between tones (ΔF) or the presentation rate (PR). They found that the B tone responses in doublets were differentially suppressed with increasing PR and that the B tones responses in triplets decreased with larger ΔF. However, the neural mechanisms underlying these animal data have yet to be explained. In this study, we built an integrate-and-fire network model of the primary auditory cortex (AC) that accurately reproduced the experimental results. Then, we extended the model to account for basic spectro-temporal features of electrocorticography (ECoG) recordings from the posteriomedial part of the Heschl's gyrus (HGPM; cortical area equivalent to the AC of monkeys), obtained from humans listening to sequences of triplets ABA-. Finally, we constructed a firing rate reduced model of the proposed integrate-and-fire network and analyzed its dynamics as function of parameters. A large network of voltage-dependent leaky integrate-and-fire neurons (3600 excitatory, 900 inhibitory) was constructed to simulate neural activity from layers 3/4 of AC during streaming of tone triplets. Parameters describing synaptic and membrane properties were based on experimental data from early studies of AC. Network structure assumed spatially-dependent probability of connections and tonotopic organization. Subpopulations of neurons were tuned to different frequencies along the tonotopic map. In-silico recordings were performed during the presentation of long sequences of triplets and/or doublets. The network’s output was derived with two types of measurements in mind: spiking activity of individual neurons and/or local populations of neurons, and local field potentials. The network spiking neural activity reproduced reliably data reports, including dependence of responses to the B tone in triplets ABA- on stimulus parameter ΔF. Approximations of average evoked potentials (AEPs) from ECoG signals recorded at four depth contacts placed over human HGPM during auditory streaming of triplets were also obtained.

Det finns ett flertal brandsimuleringsprogram på marknaden som används i olika utsträckning varav ett är Fire Dynamics Simulator (FDS). En av nackdelarna med FDS är att det kan ta mycket tid att göra en brandsimulering. Det finns brandsimuleringsprogram som med stor sannolikhet utför brandsimuleringar snabbare än FDS. För några av dessa brandsimuleringsprogram finns det inte någon dokumentation om hur resultaten som brandsimuleringsprogrammen producerar ställer sig mot det som skulle hända i verkligheten vid en brand, något som kallas att vara valideratdet vill säga programmen är inte validerade. Ett av dessa brandsimuleringsprogram är Multi-Zone Fire Model (MZ-Fire Model). Brandsimuleringsprogrammet MZ-Fire Model bygger på ett multizonkoncept framtaget av Suzuki et al. Multizonkonceptet har validerats i tidigare studier varav ett är en brand i tunnel men även bränder i mindre lokaler har prövats. Det finns utrymme för ökad kunskap om hur multizonkonceptet hanterar bränder i stora rumslokaler då det inte finns någon känd dokumentation kring detta. Det finns i dagsläget inte en enda studie som behandlar brandsimuleringsprogrammet MZ-Fire Model. I rapporten redogörs för simulerande av en brand i 4 olika rum av brandsimuleringsprogrammen MZ-Fire Model och FDS, dess simulerade värden är sedan jämförda mot varandra. / There are a number of fire simulation programs on the market that are used to varying degrees, one of which is Fire Dynamics Simulator (FDS). One of the disadvantages of FDS is that it can take a lot of time to do a fire simulation. There are fire simulation programs that are very likely to perform fire simulations faster than FDS. For some of these fire simulation programs, there is no documentation on how the results produced by the programs compare with what would happen in the event of a real fire, something called to bethat is they are not validated. One of these fire simulation programs is Multi-Zone Fire Model (MZ-Fire Model). The fire simulation program MZ-Fire Model is based on a multi-zone concept developed by Suzuki et al. The multi-zone concept has been validated in previous studies, one of which is a fire in a tunnel but fires in smaller premises have also been tested. There is room for increased knowledge about how the multi-zone concept handles fires in large rooms, as there is no known documentation on this. Currently, there is not a single study dealing with the MZ-Fire Model program. The report describes the simulation of a fire in 4 different rooms by the programs MZ-Fire Model and FDS, its simulated values ​​are then compared against each other.

A stochastic leaky integrate-and-fire neuron model was implemented in this study to simulate the spiking activity of the electrosensory "P-unit" receptor neurons of the weakly electric fish Apteronotus leptorhynchus. In the context of sensory coding, these cells have been previously shown to respond in experiment to natural random narrowband signals with either a linear or nonlinear coding scheme, depending on the intrinsic firing rate of the cell in the absence of external stimulation. It was hypothesised in this study that this duality is due to the relation of the stimulus to the neuron's excitation threshold. This hypothesis was validated with the model by lowering the threshold of the neuron or increasing its intrinsic noise, or randomness, either of which made the relation between firing rate and input strength more linear. Furthermore, synchronous P-unit firing to a common input also plays a role in decoding the stimulus at deeper levels of the neural pathways. Synchronisation and desynchronisation between multiple model responses for different types of natural communication signals were shown to agree with experimental observations. A novel result of resonance-induced synchrony enhancement of P-units to certain communication frequencies was also found.

A stochastic leaky integrate-and-fire neuron model was implemented in this study to simulate the spiking activity of the electrosensory "P-unit" receptor neurons of the weakly electric fish Apteronotus leptorhynchus. In the context of sensory coding, these cells have been previously shown to respond in experiment to natural random narrowband signals with either a linear or nonlinear coding scheme, depending on the intrinsic firing rate of the cell in the absence of external stimulation. It was hypothesised in this study that this duality is due to the relation of the stimulus to the neuron's excitation threshold. This hypothesis was validated with the model by lowering the threshold of the neuron or increasing its intrinsic noise, or randomness, either of which made the relation between firing rate and input strength more linear. Furthermore, synchronous P-unit firing to a common input also plays a role in decoding the stimulus at deeper levels of the neural pathways. Synchronisation and desynchronisation between multiple model responses for different types of natural communication signals were shown to agree with experimental observations. A novel result of resonance-induced synchrony enhancement of P-units to certain communication frequencies was also found.

This thesis describes an observation function for a dynamic data driven application system designed to produce short range forecasts of the behavior of a wildland fire. The thesis presents an overview of the atmosphere-fire model, which models the complex interactions between the fire and the surrounding weather and the data assimilation module which is responsible for assimilating sensor information into the model. Observation plays an important role in data assimilation as it is used to estimate the model variables at the sensor locations. Also described is the implementation of a portable and user friendly visualization tool which displays the locations of wildfires in the Google Earth virtual globe.

A stochastic leaky integrate-and-fire neuron model was implemented in this study to simulate the spiking activity of the electrosensory "P-unit" receptor neurons of the weakly electric fish Apteronotus leptorhynchus. In the context of sensory coding, these cells have been previously shown to respond in experiment to natural random narrowband signals with either a linear or nonlinear coding scheme, depending on the intrinsic firing rate of the cell in the absence of external stimulation. It was hypothesised in this study that this duality is due to the relation of the stimulus to the neuron's excitation threshold. This hypothesis was validated with the model by lowering the threshold of the neuron or increasing its intrinsic noise, or randomness, either of which made the relation between firing rate and input strength more linear. Furthermore, synchronous P-unit firing to a common input also plays a role in decoding the stimulus at deeper levels of the neural pathways. Synchronisation and desynchronisation between multiple model responses for different types of natural communication signals were shown to agree with experimental observations. A novel result of resonance-induced synchrony enhancement of P-units to certain communication frequencies was also found.

A stochastic leaky integrate-and-fire neuron model was implemented in this study to simulate the spiking activity of the electrosensory "P-unit" receptor neurons of the weakly electric fish Apteronotus leptorhynchus. In the context of sensory coding, these cells have been previously shown to respond in experiment to natural random narrowband signals with either a linear or nonlinear coding scheme, depending on the intrinsic firing rate of the cell in the absence of external stimulation. It was hypothesised in this study that this duality is due to the relation of the stimulus to the neuron's excitation threshold. This hypothesis was validated with the model by lowering the threshold of the neuron or increasing its intrinsic noise, or randomness, either of which made the relation between firing rate and input strength more linear. Furthermore, synchronous P-unit firing to a common input also plays a role in decoding the stimulus at deeper levels of the neural pathways. Synchronisation and desynchronisation between multiple model responses for different types of natural communication signals were shown to agree with experimental observations. A novel result of resonance-induced synchrony enhancement of P-units to certain communication frequencies was also found.

Neurons communicate by action potentials. This process can be described by very detailed biochemical models of neuronal membrane and its channels, or by simpler phenomenological models of membrane potential (integrate-and- fire models) or even by very abstract models when only time of spikes are considered. We took one particular description - stochastic leaky integrate-and-fire model - and compared it with recorded in-vivo intracellular activity of the neuron. We estimated parameters of this model, compared how the model simulation corresponds with a real neuron. It can be concluded that the data are generally consistent with the model. At a more abstract level of description, the spike trains are analyzed without considering exact membrane voltage and one asks how the external stimulus is encoded in the spike train emitted by neurons. There are many neuronal codes described in literature and we focused on the open problem of neural code responsible for spatial hearing in mammals. Several theories explaining the experimental findings have been proposed and we suggest a specific variant of so called slope-encoding model. Neuronal circuit mimick- ing auditory pathway up to the first binaural neuron was constructed and experimental results were reproduced. Finally, we estimated the minimal number of such...

Neurons communicate by action potentials. This process can be described by very detailed biochemical models of neuronal membrane and its channels, or by simpler phenomenological models of membrane potential (integrate-and- fire models) or even by very abstract models when only time of spikes are considered. We took one particular description - stochastic leaky integrate-and-fire model - and compared it with recorded in-vivo intracellular activity of the neuron. We estimated parameters of this model, compared how the model simulation corresponds with a real neuron. It can be concluded that the data are generally consistent with the model. At a more abstract level of description, the spike trains are analyzed without considering exact membrane voltage and one asks how the external stimulus is encoded in the spike train emitted by neurons. There are many neuronal codes described in literature and we focused on the open problem of neural code responsible for spatial hearing in mammals. Several theories explaining the experimental findings have been proposed and we suggest a specific variant of so called slope-encoding model. Neuronal circuit mimick- ing auditory pathway up to the first binaural neuron was constructed and experimental results were reproduced. Finally, we estimated the minimal number of such...