خيارات البحث
النتائج 1 - 3 من 3
Technologies selection for VR/AR systems development
2010
Cirulis, A., Latvia Univ. of Agriculture, Jelgava (Latvia) | Brigmanis, K., Vidzeme Univ. of Applied Sciences, Valmiera (Latvia)
Today e-learning is a term which is commonly used, but does not have a universally accepted definition, but it can be considered as technology-enhanced learning, where all types of digital technologies are used to support the learning process. Over the years some new functionality has appeared as mobile and wireless technologies (m-learning) and digital television provided possibilities for interactive study materials management (tv-learning). Latest options for training process acceleration are offered by virtual and augmented reality (VR/AR) technologies. The aim of this paper is to find solution for appropriate hardware selection before constructing VR/AR system for training needs focusing on platforms used for operators preparation to work with industrial equipment. In the beginning of the paper all hardware devices for such systems are summarized and explained. Then by using set theory and combinatorics all possible sets of input/output devices are described and calculated. Next dynamic modelling is used to create deterministic, static simulation model with an aim to ease the process of hardware selection for VR/AR training systems development. Simulation model is used for development of two pilot projects.
اظهر المزيد [+] اقل [-]Mathematical model of glycerol cycle in baker's yeast
2010
Brusbardis, V., Latvia Univ. of Agriculture, Jelgava (Latvia) | Liepins, J., University of Latvia, Riga (Latvia)
Approach of white box mathematical modelling was used to develop dynamic mathematical model of glycerol cycle in baker's yeast Saccharomyces cerevisiae and by deterministic simulations explore an interaction between glycerol cycle and glycolysis. The key process in research was reaction of artificially expressed glycerol-2-dehydrogenase (Gld2) which catalyses glycerol transition into dihydroxyacetone and reduced nicotinamide adenine dinucleotide phosphate (NADPH). We put forward hypothesis that expression of Gld2 in S. cerevisiae could increase concentration of reduced cytosolic NADPH. Michaelis-Menten equation was used to describe a rate law of reactions of the model of glycerol cycle. Kinetic parameters Km (Michaelis - Menten constant) and Vmax (maximal velocity of reaction) were taken from BRENDA database and publications. To perform deterministic simulations of the model of glycerol cycle and glycolysis, an accomplished model of glycerol cycle was introduced into the mathematical model of glycolysis of Nielsen et al. (1998). Results suggested that Gld2 reaction could run even without glycolysis as long as glycerol and oxidized nicotinamide adenine dinucleotide phosphate (NADP+) was present in the system. Intracellular concentration of glycerol had a direct impact on formation and acumulation of dihydroxyacetone. Reduced nicotinamide adenine dinucleotide (NADH) concentration decreased significantly and rapidly when glycerol cycle was switched on suggesting that it could be a limiting factor of the system.
اظهر المزيد [+] اقل [-]Dynamic model of biochemical network of Zymomonas mobilis adaptation for glycerol conversion into bioethanol
2012
Odzina, I., Latvia Univ. of Agriculture, Jelgava (Latvia)
One of the biodiesel production problems is occurrence of a significant quantity (about 10%) of the by-product – glycerol. This problem is offered to solve by adaptation of bacteria Zymomonas mobilis, which is notable for ethanol production facilities. To be able to process glycerine into ethanol using Z.mobilis bacteria, the bacteria must be modified. At the same time, computer modelling analysis is required to assess specific modification affectivity in interconnection with other processes in bacteria. Computer model results of simulated experiment to understand and predict that the cells and biological processes are essential to reduce the number of experiments. This in turn reduces the necessary financial resources and time, bio-medical biotechnology, pharmaceutical and environmental problems. The model describes conversion of glycerol into bioethanol in Z.mobilis bacterial cell. First phase of model creation is creation of a structure model based on biochemical reactions using computer software CellDesigner. On the second phase of model creation, kinetic parameters which are available in literature were identified. Using the databases KEGG, SABIO-RK, BRENDA, reactants, kinetic parameters and reaction equation types were defined. Dynamic model of Z. mobilis biochemical network was created using computer software Copasi. The dynamic model describes conversion of glycerol into bioethanol in Z.mobilis bacterial cell. In this time simulation data of the computer model of natural organisms are not to confirm laboratory experimental data. Simulation data of the computer model are not correct to prevent this problem is required parameter estimation in computer software COPASI.
اظهر المزيد [+] اقل [-]