National Repository of Grey Literature 594 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Speciation rate
Leščinskij, Artem ; Storch, David (advisor) ; Macháč, Antonín (referee)
Speciation rate is a frequency at which an original species splits into two species per unit of time. Since this rate cannot be directly determined, it must be inferred from the fossil record or a reconstructed phylogeny using appropriate diversification model or nodes and branches of a phylogenetic tree. The homogeneous birth-death process is the basic method upon which other models, such as time-dependent or density-dependent models, are based. Non-model methods such as DR statistics, node-density metrics or inverstion length of terminal branches, are methods depend on reconstructed phylogenetic trees. More complex methods include MEDUSA, BAMM, CLaDS, MTBD, or trait-dependant models. Protracted-speciation models are biologically more plausible and describe speciation as a gradual process. These methods can detect more complex diversification regimes. Tip rate determines expected species-specific rate of speciation and is less dependent on the rates of extinction and diversification; rather, it corresponds to the rate of speciation. Model identifiability is a fundamental problem limiting the estimation of the speciation rate, but this limitation can be partially overcome by new techniques such as pulled rates. Keywords: speciation rate, phylogeny, diversification, evolution, model
Řízení integračních soustav
Meduna, Jakub
This thesis describes modern methods of controlling integration systems that are commonly found in practice all around us. The aim of this thesis was to select a suitable PID controller with two degrees of freedom to control these systems and to compare the results with classical PID regulation. The evaluation was based on comparing several typical criteria of quality. The results of the simulation experiments show that the regulation by the controller with two degrees of freedom, with certain requirements for the regulation way, does not always come out as a better option for controlling integration systems. The thesis concludes with a recommendation for the selection of a controller with two degrees of freedom and a recommended procedure for the selection of its parameteres.
Simulation of processes predicted by theory of frozen plasticity
Nekola, Ondřej ; Flegr, Jaroslav (advisor) ; Ponížil, Petr (referee)
The question of the tempo of evolution is amongst the oldest conundrums in evolutionary biology and has not been satisfactorily answered yet. One of the attempts to do so is the frozen plasticity theory, which postulates that a sexually reproducing species is only capable of evolution within short periods of time after its genetic polymorphism decreases e.g. as a consequence of peripatric speciation. In the longer periods of evolutionary stasis, its evolution is limited by frequency- dependent selection and pleiotropy. In this work, I have produced an open source software simulating the respon- ses of populations of sexually reproducing individuals to varying environmental conditions. Using this software, I simulated evolution of populations with different probabilities of arising of alelles affecting more phenotypic traits and frequency- dependent selected alleles that have opposing phenotypic effects when present at the locus in one copy, respectively two copies. I observed trends predicted by the theory of frozen plasticity: slower adap- tation to instant environmental changes, lower achieved fitness and more frequent extinctions of populations with higher portions of investigated types of alleles, but only with low effect sizes and without statistical significance. For future research, it would be desirable...
Paint shop Process Improvement through Predictive Simulation
Machačová, Simona ; Hromková, Ivana (referee) ; Videcká, Zdeňka (advisor)
This thesis focuses on the use of simulation to optimise processes in a paint shop. The aim of the thesis is to analyse the existing production processes and suggest improvements using simulation. In the analytical part of the thesis, the processes in the paint shop are described in detail and Petri nets are used to describe the logic of the processes in the paint shop. In the design part of the thesis, the problem and objectives are formulated, and the design of the simulation model is presented. The design describes the elements and methods used in the Plant Simulation software in which the model is created. Furthermore, different scenarios are simulated to optimize the painting process and the deposition areas. The simulation results are compared with the actual state of the paint shop. Finally, the results are discussed and recommendations are proposed to optimize the paint shop processes using simulation. This work presents new approaches to process optimization in industrial manufacturing.
Coupled model of transformer
Adamec, Lukáš ; Huzlík, Rostislav (referee) ; Vlach, Radek (advisor)
The bachelor's thesis deals with the creation of a coupled model of transformer in the Matlab system. The coupled model connects two basic physical domains - electricity and heat transfer. It all starts with the selection of suitable equivalent circuit diagrams that represent the electrical and thermal properties. Their connection is then called as coupled model, which captures their mutual influence. An important part of the thesis is the identification of elements (thermal resistances and capacities, stray inductance, etc.) of equivalent circuit. Open-circuit and short-circuit tests are used to identify electrical elements, thermal elements are then determined from the temperature curves of the sub-parts of the transformer – core and winding. The goal of the thesis is that the output of the coupled model corresponds as closely as possible to the behavior of a real transformer. Compliance is verified by the final simulation.
Digital twin of production system using discrete simulation and MES
Mařata, Michal ; Hromková, Ivana (referee) ; Simeonov, Simeon (advisor)
The diploma thesis deals with the methodology of creating a Digital Twin of the production system and usage of discrete simulation for production scheduling. Digital Twin (also Model or Shadow) is a Digital Model of a real, for example production system, on which its operation can be simulated. The work also theoretically discusses the MES (Manufacturing Execution System), performance characteristics OEE and KPI.
Design of Microrobots – biologically inspired
Benedek, Adam ; Holoubek, Tomáš (referee) ; Simeonov, Simeon (advisor)
The bachelor’s thesis contains a comprehensive research that deals with methods, systems and various components that are used in practice in the design and production of microrobots. Subsequently, the work is dedicated to the actual design and production of the snake skeleton and locomotor system for the enlarged and simplified model of the crawling microrobot, which is inspired by living representatives from the reptile kingdom. At the end, other designs of micro-robots inspired by reptiles and their use are also mentioned.
Modeling and controling of a laboratory stand with an induction and DC motor
Musil, Pavel ; Pazdera, Ivo (referee) ; Knobloch, Jan (advisor)
This bachelor thesis deals with the theory of an asynchronous machine and the types of its management. It focuses on assembling a laboratory model with an asynchronous and DC motor connected via resolver on a common shaft. In order to set the model correctly, the asynchronous motor is first measured, the appropriate parameters are obtained and the model's behavior towards the real device is tested. The resulting part is a set of laboratory tasks possible for this model and equipment.
Design of the precast load-bearing structure of the production hall
Knespl, Vojtěch ; Čairović, Dorde (referee) ; Girgle, František (advisor)
The bachelor´s thesis is focused on the design and static calculation of selected elements of the prefabricated load-bearing structure of production hall, the development of basic drawings of the project documentation of the building and drawings of the shape and reinforcement of the solved elements in the details of the implementation documentation. Specifically, it is a T-section reinforced concrete saddle truss, rectangular columns, and headers. The thesis includes a text section that contains a description of the object, the structural system, the individual elements, loads, model, and technological construction process. Calculations were performed using Scia Engineer 21.1, IDEA StatiCa and Microsoft Excel programs.
Pharmacokinetic modelling in Positron Emission Tomography
Čaňková, Lenka ; Jiřík, Radovan (referee) ; Mézl, Martin (advisor)
This bachelor thesis deals with pharmacokinetic compartmental modelling in positron emission tomography. It includes a description of the basic pharmacokinetic variables and models. Models for selected radiopharmaceuticals are theoretically developed. Simulations of different organs in the Simulink environment have been performed for the radiopharmaceutical 18F-FDG. A brain slice model for the radiopharmaceutical [11C]-PS13 was created. Estimation of constants and optimization of models based on real data was performed. Subsequently, graphs of radiopharmaceutical concentrations as a function of time were plotted and described.

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