Volume 14, Issue 1
Worldwide Scientist
New Books
Bioprocess systems
An Application of Different Mixing Systems for Batch Cultivation of Saccharomyces cerevisiae. Part II: Multiple Objective Optimization and Model Predictive Control1-14
Mitko Petrov, Uldis Viesturs, Tatiana Ilkova, Andrejs Bērziņš, Juris Vanags, Stoyan Tzonkov
[ +/- abstract ][ full text ]
Multiple objective optimization of the initial conditions, maximal rotation speed and amplitude for a batch Saccharomyces cerevisiae cultivation using impulse and vibromixing systems is developed in this paper. The single objective function corresponds to the process productiveness and the residual glucose concentration. The multiple objective optimization problems are transformed to a single objective function with weight coefficients. A combined algorithm is applied for solving the single optimization. After this optimization the useful process productiveness increases and the residual glucose concentration at the end of the process decreases. The developed optimization and obtained results have shown that the impulse mixing systems have a better productiveness and better glucose assimilation. In addition, this system is easier for realization. The combined algorithm does not have a feedback and it does not guarantee robustness to process disturbances. For that purpose model predictive control for guarantee robustness to process disturbances is developed. The developed control algorithm - combined multiple objective optimization problem and model predictive control ensures maximal production at the end of the process and guarantees a feedback on disturbance as well as robustness to process disturbances.
Biomedical systems
Risk Factors Associated with Gestational Diabetes Mellitus15-26
Anthony Shannon, C. K. Wong
[ +/- abstract ][ full text ]
The purpose of the studies reviewed here is to consider the risk factors associated with gestational diabetes mellitus. In order to abstract general features meta-analysis is utilized as the review tool.
Reliability of a Novel Model for Drug Release from 2D HPMC-Matrices27-36
Rumiana Blagoeva, Assen Nedev
[ +/- abstract ][ full text ]
A novel model of drug release from 2D-HPMC matrices is considered. Detailed mathematical description of matrix swelling and the effect of the initial drug loading are introduced. A numerical approach to solution of the posed nonlinear 2D problem is used on the basis of finite element domain approximation and time difference method. The reliability of the model is investigated in two steps: numerical evaluation of the water uptake parameters; evaluation of drug release parameters under available experimental data. The proposed numerical procedure for fitting the model is validated performing different numerical examples of drug release in two cases (with and without taking into account initial drug loading). The goodness of fit evaluated by the coefficient of determination is presented to be very good with few exceptions. The obtained results show better model fitting when accounting the effect of initial drug loading (especially for larger values).
Ecological systems
Stability Analysis of Some Nonlinear Anaerobic Digestion Models37-48
Ivan Simeonov, Sette Diop
[ +/- abstract ][ full text ]
Abstract: The paper deals with local asymptotic stability analysis of some mass balance dynamic models (based on one and on two-stage reaction schemes) of the anaerobic digestion (AD) in CSTR. The equilibrium states for models based on one (with Monod, Contois and Haldane shapes for the specific growth rate) and on two-stage (only with Monod shapes for both the specific growth rate of acidogenic and methanogenic bacterial populations) reaction schemes have been determined solving sets of nonlinear algebraic equations using Maples. Their stability has been analyzed systematically, which provides insight and guidance for AD bioreactors design, operation and control.
A Conceptual Generalized Nets Immunological Model for Agent based Exploration of Unknown Environment49-60
Zlatogor Minchev, Dimitar Dimitrov
[ +/- abstract ][ full text ]
Exploration of unknown environment in general is a very broad area, which in the current paper is addressed more to the agent based idea and robotics. As far as the agent and its further development - multiagent modus resembles real social systems the interaction between agents could benefit from the natural mechanisms like immune system. The paper presents a conceptual model for exploration of unknown environment, which extends the immune networks' idea with some self-immunization by means of dynamic anti-body generation with application both in mobile and i-mobile robotics (Smart Homes) modeling and control, maintaining practical benefits like energy saving. The model is described in terms of the Generalized Nets Theory, thus providing a convenient and natural environment for agent-based modeling.
Algorithm for Clustering Data Set Represented by Intuitionistic Fuzzy Estimates61-68
Liudmila Todorova, Peter Vassilev
[ +/- abstract ][ full text ]
One of the main problems in the area of pattern recognition in biomedical research areas is to determine clusters of patterns with similar features. It is especially relevant in the case of intuitionistic fuzzy sets. In the present paper an iterative procedure for clustering of patterns represented by their intuitionistic fuzzy sets - degrees of membership, degrees of non-membership and indeterminacy. The procedure is open to selection and application of an appropriate to the data distribution similarity measure for intuitionistic fuzzy sets.
Synchronizing Parallel Processes using Generalized Nets69-74
Pavel Tchesmedjiev
[ +/- abstract ][ full text ]
In the present paper Generalized Nets are proposed as a common ground for synchronizing parallel processes. We will demonstrate how a GN model can be applied in the context of software maintenance procedures and present the advantages of this approach.

© 2010, BAS, Institute of Biophysics and Biomedical Engineering