142 research outputs found

    Parameter Identification of a Fed-Batch Cultivation of S. Cerevisiae using Genetic Algorithms

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    Fermentation processes as objects of modelling and high-quality control are characterized with interdependence and time-varying of process variables that lead to non-linear models with a very complex structure. This is why the conventional optimization methods cannot lead to a satisfied solution. As an alternative, genetic algorithms, like the stochastic global optimization method, can be applied to overcome these limitations. The application of genetic algorithms is a precondition for robustness and reaching of a global minimum that makes them eligible and more workable for parameter identification of fermentation models. Different types of genetic algorithms, namely simple, modified and multi-population ones, have been applied and compared for estimation of nonlinear dynamic model parameters of fed-batch cultivation of S. cerevisiae.* This work is partly supported by the National Science Fund Project MI – 1505/2005

    Application of Spatial Network Analysis in Road Accidents Based on Open Data

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    Provođenje prostorne analize temeljene na ispravnom multifunkcionalnom geografski orijentiranom modelu u domeni prometnih nesreća važan je dio cjelokupnog upravljanja prometnim sustavom. Cilj je rada demonstrirati metodologiju korištenja digitalnog modela cesta, definiranje optimalnih parametara za izradu cestovnog grafa i georeferenciranje nastalih događaja radi određivanja indeksa prostorne autokorelacije prometnih nesreća, u potpunosti koristeći otvorene podatke. Da bi se postigao taj cilj, upotrebljava se temelj međunarodne normizacije postavljen u ISO 19 100 – Geografske informacije u kombinaciji s metodom prostorne autokorelacije, proširenom za mrežu, praktično primijenjenom kroz mogućnosti programskog jezika Python kao elementa Geoinformacijskog sustava prometnih nesreća. Obrađeni su podatci otvorenog koda s geoportala OpenStreetMap, kao i stvarni arhivski podatci za 1288 teških nesreća na području grada Sofije u Bugarskoj, te je izračunat koeficijent prostorne autokorelacije kako bi se utvrdila ovisnost ili neovisnost broja prometnica nesreća između pojedinih područja svojom točnošću i pouzdanošću. Rezultat je definiranje ispravne osnove za provedbu prostorne analize s postavljanjem temelja za naknadno proučavanje različitih čimbenika i definiranje niza razloga čije će utvrđivanje dovesti do smanjenja ozljeda u prometu.Performing spatial analysis based on a correct multifunctional geographically oriented model in the domain of road accident is an important part of the overall transport system management. The aim of the paper is to demonstrate a methodology for using a digital road model, defining optimal parameters for building a road graph and georeferencing occurred events to determine a spatial autocorrelation index of road accidents, entirely using open data. To achieve this goal, the foundation of international standardization laid down in ISO 19 100 – Geographic information is used in combination with the method for spatial autocorrelation, extended for a network, practically implemented through the capabilities of the Python programming language as an element of a Geoinformation system of road accidents. Open-source data from the OpenStreetMap geoportal were processed, as well as real archive data for 1 ,288 serious accidents on the territory of the city of Sofia, Bulgaria, and a spatial autocorrelation coefficient was calculated to determine the dependence or independence of the number of road accidents between individual areas with its accuracy and reliability. The result is the definition of a correct basis for carrying out spatial analysis with the laying of a foundation for the subsequent study of various factors and the definition of a complex of reasons, the establishment of which will lead to a reduction in traffic injuries

    Razvoj konceptualnog modela geoinformacijskog sustava prometnih nesreća

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    The field of road accidents requires a specific geoinformation system to provide functionalities for creating and managing intelligent geographically-oriented spatial-temporal models for spatial analysis. The aim of this study is to present a conceptual model of a geoinformation system of road accidents, defined in accordance with the requirements of international standardization. The approach for international standardization and conceptual modeling of geoinformation, as well as the principles of object-oriented modeling, methods of abstraction and classification were used. As a result, a Use Case and a Class diagram, presented in the Unified Modeling Language, were developed. In conclusion, the standardized conceptual model is defined as an important initial stage in the creation of a geoinformation system of road accidents, which is related to the correct formalized description of the domain and the presentation of structural types of geoinformation processes, and subsequently can be automatically and in the unified manner transposed into a functional physical model for the analysis of road accidents.Područje prometnih nesreća zahtijeva specifičan geoinformacijski sustav koji bi omogućio funkcionalnosti za kreiranje i upravljanje inteligentnim geografski orijentiranim prostorno-vremenskim modelima za prostornu analizu. Cilj je ovoga rada prikazati konceptualni model geoinformacijskog sustava prometnih nesreća definiran u skladu sa zahtjevima međunarodne normizacije. Korišten je pristup za međunarodnu normizaciju i konceptualno modeliranje geoinformacija, kao i principi objektno orijentiranog modeliranja, metode apstrakcije i klasifikacije. Kao rezultat toga razvijeni su slučaj upotrebe i dijagram klasa (use case and a class diagram), predstavljeni u UML-u. Zaključno, normirani je konceptualni model definiran kao važna početna faza u izradi geoinformacijskog sustava prometnih nesreća koja se odnosi na točan formalizirani opis domene i prikaz strukturnih tipova geoinformacijskih procesa, a potom se može automatski i objedinjeno transponirati u funkcionalni fizički model za analizu prometnih nesreća

    Development of a Conceptual Model of a Road Accident Geoinformation System

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    Područje prometnih nesreća zahtijeva specifičan geoinformacijski sustav koji bi omogućio funkcionalnosti za kreiranje i upravljanje inteligentnim geografski orijentiranim prostorno-vremenskim modelima za prostornu analizu. Cilj je ovoga rada prikazati konceptualni model geoinformacijskog sustava prometnih nesreća definiran u skladu sa zahtjevima međunarodne normizacije. Korišten je pristup za međunarodnu normizaciju i konceptualno modeliranje geoinformacija, kao i principi objektno orijentiranog modeliranja, metode apstrakcije i klasifikacije. Kao rezultat toga razvijeni su slučaj upotrebe i dijagram klasa (use case and a class diagram), predstavljeni u UML-u. Zaključno, normirani je konceptualni model definiran kao važna početna faza u izradi geoinformacijskog sustava prometnih nesreća koja se odnosi na točan formalizirani opis domene i prikaz strukturnih tipova geoinformacijskih procesa, a potom se može automatski i objedinjeno transponirati u funkcionalni fizički model za analizu prometnih nesreća.The field of road accidents requires a specific geoinformation system to provide functionalities for creating and managing intelligent geographically-oriented spatial-temporal models for spatial analysis. The aim of this study is to present a conceptual model of a geoinformation system of road accidents, defined in accordance with the requirements of international standardization. The approach for international standardization and conceptual modeling of geoinformation, as well as the principles of object-oriented modeling, methods of abstraction and classification were used. As a result, a Use Case and a Class diagram, presented in the Unified Modeling Language, were developed. In conclusion, the standardized conceptual model is defined as an important initial stage in the creation of a geoinformation system of road accidents, which is related to the correct formalized description of the domain and the presentation of structural types of geoinformation processes, and subsequently can be automatically and in the unified manner transposed into a functional physical model for the analysis of road accidents

    Tuning Genetic Algorithm Parameters to Improve Convergence Time

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    Fermentation processes by nature are complex, time-varying, and highly nonlinear. As dynamic systems their modeling and further high-quality control are a serious challenge. The conventional optimization methods cannot overcome the fermentation processes peculiarities and do not lead to a satisfying solution. As an alternative, genetic algorithms as a stochastic global optimization method can be applied. For the purpose of parameter identification of a fed-batch cultivation of S. cerevisiae altogether four kinds of simple and four kinds of multipopulation genetic algorithms have been considered. Each of them is characterized with a different sequence of implementation of main genetic operators, namely, selection, crossover, and mutation. The influence of the most important genetic algorithm parameters-generation gap, crossover, and mutation rates has-been investigated too. Among the considered genetic algorithm parameters, generation gap influences most significantly the algorithm convergence time, saving up to 40% of time without affecting the model accuracy

    Lipid Composition of Paulownia Seeds Grown in Bulgaria

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    DergiPark: 246128trakyafbdThe chemical composition of seeds from paulownia (Paulownia tomentosa) was investigated. The main components in the triacylglycerol fraction of the oil were linoleic (64.1%), oleic (21.2%) and palmitic acids (7.3%). ?-Tocopherol (approx. 100.0%) predominated in the tocopherol fraction, and in the sterol fraction – ß-sitosterol (79.2%), campesterol (10.3%) and stigmasterol (7.7%). In the seeds were established 10.6% protein, 9.5% cellulose and 38.2% hydrolysable carbohydrates

    Antitumor activity of Bulgarian herb Tribulus terrestris L. on human breast cancer cells

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    Medicinal plants have been intensively studied as a source of antitumor compounds. Due to the beneficial climate conditions Bulgarian herbs have high pharmacological potential. Currently, the antitumor effect of the Bulgarian medicinal plant Tribulus terrestris L. on human cancer cell lines is not studied. The main active compounds of the plant are the steroid saponins.The present study aims to analyze the effect on cell viability and apoptotic activity of total extract and saponin fraction of Bulgarian Tribulus terrestris L. on human breast cancer (MCF7) and normal (MCF10A) cell lines. Antitumor effect was established by МТТ cell viability assay and assessment of apoptotic potential was done through analysis of genomic integrity (DNA fragmentation assay) and analysis of morphological cell changes (Fluorescence microscopy). The results showed that total extract of the herb has a marked dose-dependent inhibitory effect on viability of MCF7 cells (half maximal inhibitory concentration is 15 μg/ml). Cell viability of MCF10A was moderately decreased without visible dose-dependent effect. The saponin fraction has increased inhibitory effect on breast cancer cells compared to total extract. Morphological changes and DNA fragmentation were observed as markers for early and late apoptosis predominantly in tumor cells after treatment. Apoptotic processes were intensified with the increase of treatment duration.The obtained results are the first showing selective antitumor activity of Bulgarian Tribulus terrestris L. on human cancer cells in vitro. Apoptotic processes are involved in the antitumor mechanisms induced by the herb. This results give directions for future investigations concerning detailed assessment of its pharmacological potential

    Standard karyotyping - a look through the European guidelines

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    Standard karyotyping is a method for genetic testing for chromosomal aberrations, based on specific clinical indications. Despite the progress in the field of molecular genetic testing, it still remains the first choice for genetic testing in developing countries due to financial and economic factors. In 2019, the latest European guidelines for constitutional cytogenomic analysis were released. They include general and specific guidelines for pre-analytical recommendation, sample preparation, analysis and reporting. Possibilities, limitations and minimum requirements for specific genetic testings are listed. Following the established European guidelines for genetic analysis and/or re-contacting patients with a possible genetic diagnosis will provide up-to-date medical service. Each laboratory should apply validated protocols for testing, based on the newly introduced recommendations by leading in the field organizations.Standard karyotyping is a method for genetic testing for chromosomal aberrations, based on specific clinical indications. Despite the progress in the field of molecular genetic testing, it still remains the first choice for genetic testing in developing countries due to financial and economic factors. In 2019, the latest European guidelines for constitutional cytogenomic analysis were released. They include general and specific guidelines for pre-analytical recommendation, sample preparation, analysis and reporting. Possibilities, limitations and minimum requirements for specific genetic testings are listed. Following the established European guidelines for genetic analysis and/or re-contacting patients with a possible genetic diagnosis will provide up-to-date medical service. Each laboratory should apply validated protocols for testing, based on the newly introduced recommendations by leading in the field organizations

    Schwann Cells Overexpressing FGF-2 Alone or Combined with Manual Stimulation Do Not Promote Functional Recovery after Facial Nerve Injury

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    Purpose. To determine whether transplantation of Schwann cells (SCs) overexpressing different isoforms of fibroblast growth factor 2 (FGF-2) combined with manual stimulation (MS) of vibrissal muscles improves recovery after facial nerve transection in adult rat. Procedures. Transected facial nerves were entubulated with collagen alone or collagen plus naïve SCs or transfected SCs. Half of the rats received daily MS. Collateral branching was quantified from motoneuron counts after retrograde labeling from 3 facial nerve branches. Quality assessment of endplate reinnervation was combined with video-based vibrissal function analysis. Results. There was no difference in the extent of collateral axonal branching. The proportion of polyinnervated motor endplates for either naïve SCs or FGF-2 over-expressing SCs was identical. Postoperative MS also failed to improve recovery. Conclusions. Neither FGF-2 isoform changed the extent of collateral branching or polyinnervation of motor endplates; furthermore, this motoneuron response could not be overridden by MS
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