### Examinando por Autor "Ospina, J."

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Ítem Analysis of a generalized model for influenza including differential susceptibility due to immunosuppression(SPIE-INT SOC OPTICAL ENGINEERING, 2014-01-01) Hincapié, D.; Ospina, J.; Hincapié, D.; Ospina, J.; Universidad EAFIT. Departamento de Ciencias; Lógica y ComputaciónMás... Recently, a mathematical model of pandemic influenza was proposed including typical control strategies such as antivirals, vaccination and school closure; and considering explicitly the effects of immunity acquired from the early outbreaks on the ulterior outbreaks of the disease. In such model the algebraic expression for the basic reproduction number (without control strategies) and the effective reproduction number (with control strategies) were derived and numerically estimated. A drawback of this model of pandemic influenza is that it ignores the effects of the differential susceptibility due to immunosuppression and the effects of the complexity of the actual contact networks between individuals. We have developed a generalized model which includes such effects of heterogeneity. Specifically we consider the influence of the air network connectivity in the spread of pandemic influenza and the influence of the immunosuppresion when the population is divided in two immune classes. We use an algebraic expression, namely the Tutte polynomial, to characterize the complexity of the contact network. Until now, The influence of the air network connectivity in the spread of pandemic influenza has been studied numerically, but not algebraic expressions have been used to summarize the level of network complexity. The generalized model proposed here includes the typical control strategies previously mentioned (antivirals, vaccination and school closure) combined with restrictions on travel. For the generalized model the corresponding reproduction numbers will be algebraically computed and the effect of the contact network will be established in terms of the Tutte polynomial of the network. © 2014 Copyright SPIE.Más... Ítem Analysis of the boundary conditions for pyramidal spine fins in extended surface heat transfer(WITPress, 2014-01-01) Carranza, R.G.; Ospina, J.; Carranza, R.G.; Ospina, J.; Universidad EAFIT. Departamento de Ciencias; Lógica y ComputaciónMás... Many studies are conducted for pyramidal spine fins relating to temperature profiles and fin efficiencies. However, it is found that a deeper look into the boundary conditions is required. The conditions at the base are simple enough, but the conditions at the tip are more complicated. Despite what condition is applied to the tip, the value at the tip actually has a specific value that is a function of the square root of the Biot number. This result is proven using basic principles from calculus, like the Limit and L’Hospital’s rule. © 2014 WIT Press.Más... Ítem Approximated analytical solution to an Ebola optimal control problem(Board Members, 2016-01-01) Hincapié-Palacio, D.; Ospina, J.; Torres, D.F.M.; Hincapié-Palacio, D.; Ospina, J.; Torres, D.F.M.; Universidad EAFIT. Departamento de Ciencias; Lógica y ComputaciónMás... An analytical expression for the optimal control of an Ebola problem is obtained. The analytical solution is found as a first-order approximation to the Pontryagin Maximum Principle via the Euler-Lagrange equation. An implementation of the method is given using the computer algebra system Maple. Our analytical solutions confirm the results recently reported in the literature using numerical methods.Más... Ítem Bases para la modelación de epidemias: El caso del síndrome respiratorio agudo severo en Canadá(Universidad Nacional de Colombia, 2007-01-01) Hincapié, D.; Ospina, J.; Hincapié, D.; Ospina, J.; Universidad EAFIT. Departamento de Ciencias; Lógica y ComputaciónMás... Objective: Severe acute respiratory syndrome propagation in Canada during 2003 is analysed by means of simple models, comparing the influence of isolation measures on two epidemic waves. Methods: Deterministic susceptible-infected and susceptible-infected-removed models were used for both epidemic waves, using official published information. NLREG 6.2 was used for estimating deterministic parameters and analytical solutions were obtained with Maple 9 software. Dynamical indicators were obtained for the epidemic. Results: Suitable adjustment of the data was observed with both models, but smaller adjustment was observed during the second wave with the non- removed model. The highest rate of infectiousness was shown (35 new cases per 10 000 susceptible people) during the second wave (with R0 near to one), in spite of presenting greater incidence (8.8 cases per day), compensated for by a high rate of removal (11,5 cases per day) which lasted less than the epidemic (11,1 days), and a lower rate of attack (1 case per each 100 susceptible people). Conclusions: The susceptible-infected model can be useful during an epidemic's initial phase (prior to removal); however, closer monitoring of an epidemic's development is required for modelling the strength of removal and deriving useful information for decision-making.Más... Ítem Biomedical computer vision using computer algebra: Analysis of a case of rhinocerebral mucormycosis in a diabetic boy(Springer Science + Business Media, 2010-01-01) Vélez, M.; Ospina, J.; Vélez, M.; Ospina, J.; Universidad EAFIT. Departamento de Ciencias; Lógica y ComputaciónMás... Computer algebra is applied to biomedical computer vision. Specifically certain biomedical images resulting from a case of rhinocerebral mucormysocis in a diabetic boy are analyzed using techniques in computational geometry and in algebraic-geometric topology. We apply convolution and deblurring via diffusion equation from the side of computational geometry and knot theory, graph theory and singular homology form the side of algebraic-geometric topology. Our strategy consists in to represent the biomedical images using algebraic structures in such way that the peculiarities of the images are represented using algebraic complexities. With our strategy we obtain an automatic procedure for the analysis and the diagnostic based on biomedical images. © 2010 Springer-Verlag Berlin Heidelberg.Más... Ítem Computing Tutte polynomials of contact networks in classrooms(SPIE-INT SOC OPTICAL ENGINEERING, 2013-01-01) Hincapié, D.; Ospina, J.; Hincapié, D.; Ospina, J.; Universidad EAFIT. Departamento de Ciencias; Lógica y ComputaciónMás... Objective: The topological complexity of contact networks in classrooms and the potential transmission of an infectious disease were analyzed by sex and age. Methods: The Tutte polynomials, some topological properties and the number of spanning trees were used to algebraically compute the topological complexity. Computations were made with the Maple package GraphTheory. Published data of mutually reported social contacts within a classroom taken from primary school, consisting of children in the age ranges of 4-5, 7-8 and 10-11, were used. Results: The algebraic complexity of the Tutte polynomial and the probability of disease transmission increases with age. The contact networks are not bipartite graphs, gender segregation was observed especially in younger children. Conclusion: Tutte polynomials are tools to understand the topology of the contact networks and to derive numerical indexes of such topologies. It is possible to establish relationships between the Tutte polynomial of a given contact network and the potential transmission of an infectious disease within such network. © 2013 SPIE.Más... Ítem The Critical Proportion of Immune Individuals needed to Control Hepatitis B(SPIE-INT SOC OPTICAL ENGINEERING, 2016-05-13) Ospina, J.; Hincapié-Palacio, D.; Ospina, J.; Hincapié-Palacio, D.; Universidad EAFIT. Departamento de Ciencias; Lógica y ComputaciónMás... We estimate the critical proportion of immunity (Pc) to control hepatitis B in Medellin - Colombia, based on a random population survey of 2077 individuals of 6-64 years of age. The force of infection (Fi) was estimated according to empirical data of susceptibility by age S(a), assuming a quadratic expression. Parameters were estimated by adjusting data to a nonlinear regression. Fi was defined by -(ds(a)/da)/s(a) and according to the form of the empirical curve S(a) we assume a quadratic expression given by S(a)= Ea2+Ba+C. Then we have the explicit expression for the accumulated Fi by age given by F(a) = -a(Ea+B)/c. The expression of average infection age A is obtained as A = L + EL3/(3C)+BL2/(2C) and the basic reproductive number R-0 is obtained as R-0 = 1 + 6C/(6C+2EL2+3BL). From the las result we obtain the Pc given by Pc=6C/(12C+2EL2+3BL). Numerical simulations were performed with the age-susceptibility proportion and initial values (a=0.02, b=20, c=100), obtaining an adjusted coefficient of multiple determination of 64.83%. According to the best estimate, the algebraic expressions for S(a) and the Fi were derived. Using the result of Fi, we obtain A = 30, L = 85; R-0 CI 95%: 1.42 - 1.64 and Pc: 0-0.29. These results indicate that at the worst case, to maintain control of the disease should be immunes at least 30% of susceptible individuals. Similar results were obtained by sex and residential area.Más... Ítem The development of a peak-time criterion for designing controlled-release devices(ELSEVIER SCIENCE BV, 2016-08-25) Simon, L.; Ospina, J.; Simon, L.; Ospina, J.; Universidad EAFIT. Departamento de Ciencias; Lógica y ComputaciónMás... This work consists of estimating dynamic characteristics for topically-applied drugs when the magnitude of the flux increases to a maximum value, called peak flux, before declining to zero. This situation is typical of controlled- released systems with a finite donor or vehicle volume. Laplace transforms were applied to the governing equations and resulted in an expression for the flux in terms of the physical characteristics of the system. After approximating this function by a second-order model, three parameters of this reduced structure captured the essential features of the original process. Closed-form relationships were then developed for the peak flux and time-to-peak based on the empirical representation. Three case studies that involve mechanisms, such as diffusion, partitioning, dissolution and elimination, were selected to illustrate the procedure. The technique performed successfully as shown by the ability of the second-order flux to match the prediction of the original transport equations. A main advantage of the proposed method is that it does not require a solution of the original partial differential equations. Less accurate results were noted for longer lag times. (C) 2016 Elsevier B.V. All rights reserved.Más... Ítem Dynamics of an Electrochemical Biosensor for the Detection of Toxic Substances in Water(SPIE-INT SOC OPTICAL ENGINEERING, 2016-01-01) Simon, L.; Ospina, J.; Simon, L.; Ospina, J.; Universidad EAFIT. Departamento de Ciencias; Lógica y ComputaciónMás... A proposed analytical method focuses on electrolyte transport to the electrode of an electrochemical cell. The recombinant Escherichia coli whole-cell biosensor detects toxicity in water based on a set of biochemical reactors. Previous contributions elucidated the kinetics of product formation and validated a mathematical model for its diffusion in the chamber. This work introduces an approach to investigate the dynamics of the probe using Laplace transforms and an effective time constant. The transfer function between the electrolyte production and the total current revealed a faster response for larger electrode radii. Both the first-order and effective time constants increased with the chamber height and radius. Separation of variables yields closed-form solutions and helps estimate the kinetics of p-aminophenol generation. When the bacteria were exposed to phenol concentrations of 1.6, 8.3 and 16 ppm, the corresponding overall rate constants were 5.11x10(-7), 1.13x10(-6) and 1.99x10(-6) (product concentration unit/s(2)), respectively. In addition to parameter estimation, the method can be applied to perform sensitivity analysis and aid manufacturers in meeting design specifications of biosensors.Más... Ítem Mathematical model for dengue with three states of infection(SPIE-INT SOC OPTICAL ENGINEERING, 2012-01-01) Hincapie, D.; Ospina, J.; Hincapie, D.; Ospina, J.; Universidad EAFIT. Departamento de Ciencias; Lógica y ComputaciónMás... A mathematical model for dengue with three states of infection is proposed and analyzed. The model consists in a system of differential equations. The three states of infection are respectively asymptomatic, partially asymptomatic and fully asymptomatic. The model is analyzed using computer algebra software, specifically Maple, and the corresponding basic reproductive number and the epidemic threshold are computed. The resulting basic reproductive number is an algebraic synthesis of all epidemic parameters and it makes clear the possible control measures. The microscopic structure of the epidemic parameters is established using the quantum theory of the interactions between the atoms and radiation. In such approximation, the human individual is represented by an atom and the mosquitoes are represented by radiation. The force of infection from the mosquitoes to the humans is considered as the transition probability from the fundamental state of atom to excited states. The combination of computer algebra software and quantum theory provides a very complete formula for the basic reproductive number and the possible control measures tending to stop the propagation of the disease. It is claimed that such result may be important in military medicine and the proposed method can be applied to other vector-borne diseases. © 2012 SPIE.Más... Ítem On the effusion time of drugs from the open pore of a spherical vesicle(ELSEVIER SCIENCE BV, 2016-06-01) Simon, L.; Ospina, J.; Simon, L.; Ospina, J.; Universidad EAFIT. Departamento de Ciencias; Lógica y ComputaciónMás... Solute permeation through a spherical liposomal vesicle was analyzed using Fick's second law and a mixed Neumann-Dirichlet boundary condition. The first-principles approach was necessary to help calculate the effusion time of a medication through a pore located on the surface of the device. An infinite series of Bessel functions represented the concentration in the Laplace domain. This method yielded closed-form expressions for the characteristic time and the Laplace-transformed fraction of drug released, which was approximated by the first term of the series. The time constant was inversely proportional to the diffusion coefficient in the system and decreased as the pore size increased. It took 4 times the effusion time to unload nearly ninety-eight percent of the pharmaceutical ingredient. (C) 2016 Elsevier B.V. All rights reserved.Más... Ítem Optimal control in a model of malaria with differential susceptibility(SPIE-INT SOC OPTICAL ENGINEERING, 2014-01-01) Hincapié, D.; Ospina, J.; Hincapié, D.; Ospina, J.; Universidad EAFIT. Departamento de Ciencias; Lógica y ComputaciónMás... A malaria model with differential susceptibility is analyzed using the optimal control technique. In the model the human population is classified as susceptible, infected and recovered. Susceptibility is assumed dependent on genetic, physiological, or social characteristics that vary between individuals. The model is described by a system of differential equations that relate the human and vector populations, so that the infection is transmitted to humans by vectors, and the infection is transmitted to vectors by humans. The model considered is analyzed using the optimal control method when the control consists in using of insecticide-treated nets and educational campaigns; and the optimality criterion is to minimize the number of infected humans, while keeping the cost as low as is possible. One first goal is to determine the effects of differential susceptibility in the proposed control mechanism; and the second goal is to determine the algebraic form of the basic reproductive number of the model. All computations are performed using computer algebra, specifically Maple. It is claimed that the analytical results obtained are important for the design and implementation of control measures for malaria. It is suggested some future investigations such as the application of the method to other vector-borne diseases such as dengue or yellow fever; and also it is suggested the possible application of free software of computer algebra like Maxima. © 2014 Copyright SPIE.Más... Ítem Possible quantum algorithms for the Bollobás-Riordan-Tutte polynomial of a ribbon graph(SPIE-INT SOC OPTICAL ENGINEERING, 2008-01-01) Velez, M.; Ospina, J.; Velez, M.; Ospina, J.; Universidad EAFIT. Departamento de Ciencias; Lógica y ComputaciónMás... Three possible quantum algorithms, for the computation of the Bollobás-Riordan-Tutte polynomial of a given ribbon graph, are presented and discussed. The first possible algorithm is based on the spanning quasi-trees expansion for generalized Tutte polynomials of generalized graphs and on a quantum version of the Binary Decision Diagram (BDD) for quasi-trees . The second possible algorithm is based on the relation between the Kauffman bracket and the Tutte polynomial; and with an application of the recently introduced Aharonov-Arad-Eban-Landau quantum algorithm. The third possible algorithm is based on the relation between the HOMFLY polynomial and the Tutte polynomial; and with an application of the Wocjan-Yard quantum algorithm. It is claimed that these possible algorithms may be more efficient that the best known classical algorithms. These three algorithms may have interesting applications in computer science at general or in computational biology and bio-informatics in particular. A line for future research based on the categorification project is mentioned.Más... Ítem Possible topological quantum computation via khovanov homology: D-brane topological quantum computer(SPIE-INT SOC OPTICAL ENGINEERING, 2009-01-01) Vélez, M.; Ospina, J.; Vélez, M.; Ospina, J.; Universidad EAFIT. Departamento de Ciencias; Lógica y ComputaciónMás... A model of a D-Brane Topological Quantum Computer (DBTQC) is presented and sustained. The model isbased on four-dimensional TQFTs of the Donaldson-Witten and Seiber-Witten kinds. It is argued that the DBTQC is able to compute Khovanov homology for knots, links and graphs. The DBTQC physically incorporates the mathematical process of categorification according to which the invariant polynomials for knots, links and graphs such as Jones, HOMFLY, Tutte and Bollobás-Riordan polynomials can be computed as the Euler characteristics corresponding to special homology complexes associated with knots, links and graphs. The DBTQC is conjectured as a powerful universal quantum computer in the sense that the DBTQC computes Khovanov homology which is considered like powerful that the Jones polynomial. © 2009 SPIE.Más... Ítem Prediction of in-vivo iontophoretic drug release data from in-vitro experiments-insights from modeling(ELSEVIER SCIENCE INC, 2015-12-01) Simon, L.; Ospina, J.; Ita, K.; Simon, L.; Ospina, J.; Ita, K.; Universidad EAFIT. Departamento de Ciencias; Lógica y ComputaciónMás... A strategy was developed to predict in-vivo plasma drug levels from data collected during in-vitro transdermal iontophoretic delivery experiments. The method used the principle of mass conservation and the Nernst-Planck flux equation to describe molecular transport across the skin. Distribution and elimination of the drug in the body followed a one- or two-compartment open model. Analytical expressions for the relaxation constant and plasma drug concentration were developed using Laplace transforms. The steady-state dermal flux was appropriate for predicting drug absorption under in-vivo conditions only when the time constant in the skin was far greater than its value in the blood compartment. A simulation study was conducted to fully assess the performance of estimations based on the equilibrium flux approximation. The findings showed that the normalized integral of squared error decreased exponentially as the ratio of the two time constants (blood/skin) increased. In the case of a single compartment, the error was reduced from 0.15 to 0.016 when the ratio increased from 10 to 100. The methodology was tested using plasma concentrations of a growth-hormone releasing factor in guinea pigs and naloxone in rats. © 2015 Elsevier Inc. All rights reserved.Más... Ítem Quantum hypercomputation based on the dynamical algebra su(1, 1)(IOP PUBLISHING LTD, 2006-10-06) Sicard, A.; Ospina, J.; Vélez, M.; Sicard, A.; Ospina, J.; Vélez, M.; Universidad EAFIT. Departamento de Ciencias; Lógica y ComputaciónMás... An adaptation of Kieu's hypercomputational quantum algorithm (KHQA) is presented. The method that was used was to replace the Weyl-Heisenberg algebra by other dynamical algebra of low dimension that admits infinite-dimensional irreducible representations with naturally defined generalized coherent states. We have selected the Lie algebra , because this algebra possesses the necessary characteristics to realize the hypercomputation and also because such algebra has been identified as the dynamical algebra associated with many relatively simple quantum systems. In addition to an algebraic adaptation of KHQA over the algebra , we presented an adaptation of KHQA over some concrete physical referents: the infinite square well, the infinite cylindrical well, the perturbed infinite cylindrical well, the Pöschl-Teller potentials, the Holstein-Primakoff system and the Laguerre oscillator. We conclude that it is possible to have many physical systems within condensed matter and quantum optics in which it is possible to consider an implementation of KHQA. © 2006 IOP Publishing Ltd.Más... Ítem Solving stochastic epidemiological models using computer algebra(SPIE-INT SOC OPTICAL ENGINEERING, 2011-01-01) Hincapie, D.; Ospina, J.; Hincapie, D.; Ospina, J.; Universidad EAFIT. Departamento de Ciencias; Lógica y ComputaciónMás... Mathematical modeling in Epidemiology is an important tool to understand the ways under which the diseases are transmitted and controlled. The mathematical modeling can be implemented via deterministic or stochastic models. Deterministic models are based on short systems of non-linear ordinary differential equations and the stochastic models are based on very large systems of linear differential equations. Deterministic models admit complete, rigorous and automatic analysis of stability both local and global from which is possible to derive the algebraic expressions for the basic reproductive number and the corresponding epidemic thresholds using computer algebra software. Stochastic models are more difficult to treat and the analysis of their properties requires complicated considerations in statistical mathematics. In this work we propose to use computer algebra software with the aim to solve epidemic stochastic models such as the SIR model and the carrier-borne model. Specifically we use Maple to solve these stochastic models in the case of small groups and we obtain results that do not appear in standard textbooks or in the books updated on stochastic models in epidemiology. From our results we derive expressions which coincide with those obtained in the classical texts using advanced procedures in mathematical statistics. Our algorithms can be extended for other stochastic models in epidemiology and this shows the power of computer algebra software not only for analysis of deterministic models but also for the analysis of stochastic models. We also perform numerical simulations with our algebraic results and we made estimations for the basic parameters as the basic reproductive rate and the stochastic threshold theorem. We claim that our algorithms and results are important tools to control the diseases in a globalized world. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).Más... Ítem Spatial epidemic patterns recognition using computer algebra(SPRINGER, 2007-01-01) Hincapié, D.; Ospina, J.; Hincapié, D.; Ospina, J.; Universidad EAFIT. Departamento de Ciencias; Lógica y ComputaciónMás... An exploration in Symbolic Computational bio-surveillance is showed. The main obtained results are that the geometry of the habitat determines the critical parameters via the zeroes of the Bessel functions and the explicit forms of the static and non-static spatial epidemic patterns. © Springer-Verlag Berlin Heidelberg 2007.Más... Ítem A three-dimensional semi-analytical solution for predicting drug release through the orifice of a spherical device(ELSEVIER SCIENCE BV, 2016-07-25) Simon, L.; Ospina, J.; Simon, L.; Ospina, J.; Universidad EAFIT. Departamento de Ciencias; Lógica y ComputaciónMás... Three-dimensional solute transport was investigated for a spherical device with a release hole. The governing equation was derived using the Fick's second law. A mixed Neumann-Dirichlet condition was imposed at the boundary to represent diffusion through a small region on the surface of the device. The cumulative percentage of drug released was calculated in the Laplace domain and represented by the first term of an infinite series of Legendre and modified Bessel functions of the first kind. Application of the Zakian algorithm yielded the time-domain closed-form expression. The first-order solution closely matched a numerical solution generated by Mathematica (R). The proposed method allowed computation of the characteristic time. A larger surface pore resulted in a smaller effective time constant. The agreement between the numerical solution and the semi-analytical method improved noticeably as the size of the orifice increased. It took four time constants for the device to release approximately ninety-eight of its drug content. © 2016 Elsevier B.V. All rights reserved.Más... Ítem Two qutrits universal quantum gates from the nine-dimensional unitary solutions of the Yang-Baxter equation(SPIE-INT SOC OPTICAL ENGINEERING, 2007-04-25) Vélez, M.; Ospina, J.; Vélez, M.; Ospina, J.; Universidad EAFIT. Departamento de Ciencias; Lógica y ComputaciónMás... Using the Kauffman-Lomonaco method, some two-qutrits universal quantum gates are derived from the nine-dimensional unitary solutions of the Yang-Baxter equations associated with algebraic structures like the partial transpose operator and the dihedral group, which admit three dimensional representations. The Yang-Baxterization method given by Zhang-Kauffman-Ge is continuously used to obtain two-qutrits quantum gates and certain Hamiltonians for the evolution of the quantum gates are obtained, being such Hamiltonians interpreted as physical Hamiltonians of chain of particles of spin 1. Finally, the generalization for systems of two qudits is presented in the case of Yang-Baxterization of representations of braided monoidal algebra like the BH algebra and the bicolored Birman-Wenzl-Muraki algebra For these algebras the corresponding two-qudits quantum gates are constructed jointly with the associated Hamiltonians interpreted like physical chains of particles with spin d . It is conjectured that the derived two-qdits quantum gates and the Hamiltonians may be implemented over bi-dimensional lattice systems like anyons systems or more generally over any physical systems ruled by the Yang-Baxter equations.Más...