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https://hdl.handle.net/10784/4547

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AIR-MODELLING: A tool for gesture-based solid modelling in context during early design stages in AR environments
(ELSEVIER SCIENCE BV, 2015-01-01) Arroyave-Tobon, Santiago; Osorio-Gomez, Gilberto; Cardona-McCormick, Juan F.; Arroyave-Tobon, Santiago; Osorio-Gomez, Gilberto; Cardona-McCormick, Juan F.; Universidad EAFIT. Departamento de Ciencias; Lógica y Computación
Augmented reality (AR) technologies are just being used as interface in CAD tools allowing the user to perceive 3D models over a real environment. The influence of the use of AR in the conceptualization of products whose configuration, shape and dimensions depend mainly on the context remains unexplored. We aimed to prove that modelling in AR environments allows to use the context in real-time as an information input for making the iterative design process more efficient. In order to prove that, we developed a tool called AIR-MODELLING in which the designer is able to create virtual conceptual products by hand gestures meanwhile he/she is interacting directly with the real scenario. We conducted a test for comparing designers' performance using AIR-MODELLING and a traditional CAD system. We obtained an average reduction of 44% on the modeling time in 76% of the cases. We found that modelling in AR environments using the hands as interface allows the designer to quickly and efficiently conceptualize potential solutions using the spatial restrictions of the context as an information input in real-time. Additionally, modelling in a natural scale, directly over the real scene, prevents the designer from drawing his/her attention on dimensional details and allows him/her to focus on the product itself and its relation with the environment. © 2014 Elsevier B.V. All rights reserved.
Algebraic analysis of social networks for bio-surveillance: the cases of SARS-Beijing-2003 and AH1N1 influenza-Mexico-2009.
(SPRINGER-VERLAG BERLIN, 2011-01-01) Hincapié D; Ospina J; Hincapié D; Ospina J; Universidad EAFIT. Departamento de Ciencias; Lógica y Computación
Algebraic analysis of social networks exhibited by SARS-Beijing-2003 and AH1N1 flu-Mexico-2009 was realized. The main tools were the Tutte polynomials and Maple package Graph-Theory. The topological structures like graphs and networks were represented by invariant polynomials. The evolution of a given social network was represented like an evolution of the algebraic complexity of the corresponding Tutte polynomial. The reduction of a given social network was described like an involution of the algebraic complexity of the associated Tutte polynomial. The outbreaks of SARS and AH1N1 Flu were considered like represented by a reduction of previously existing contact networks via the control measures executed by health authorities. From Tutte polynomials were derived numerical indicators about efficiency of control measures.
Ambientes de Aprendizaje en el Siglo XXI
(2008-11-01) Correa, Francisco Jose; CORREA, FRANCISCO JOSE; Universidad EAFIT. Departamento de Ciencias; Lógica y Computación
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 Computación
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.
Arboles de forzamiento semantico
(Fondo Editorial Universidad EAFIT, 2001-01-01) Sierra, Manuel Hernando; SIERRA, MANUEL HERNANDO; Universidad EAFIT. Departamento de Ciencias; Lógica y Computación
Arboles de forzamiento semántico para el sistema básico con afirmación y negación alternas
(2006-01-01) Sierra, Manuel Hernando; SIERRA, MANUEL HERNANDO; Universidad EAFIT. Departamento de Ciencias; Lógica y Computación
Arboles de forzamiento semántico para operaciones entre conjuntos
(2017-01-01) Sierra, Manuel Hernando; SIERRA, MANUEL HERNANDO; Universidad EAFIT. Departamento de Ciencias; Lógica y Computación
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 Computación
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.
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 Computación
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.
Caracterización deductiva de los árboles de forzamiento semántico
(Fondo Editorial Universidad EAFIT, 2006-01-01) Sierra, Manuel Hernando; SIERRA, MANUEL HERNANDO; Universidad EAFIT. Departamento de Ciencias; Lógica y Computación
Caracterización semántica de la jerarquía SCR-n
(2007-01-01) Sierra, Manuel Hernando; SIERRA, MANUEL HERNANDO; Universidad EAFIT. Departamento de Ciencias; Lógica y Computación
Computación cuántica geométrica: modelo de 3 estados
(Sociedad Colombiana de Física, 2004-01-01) Sicard, Andrés; Sicard, Andrés; Universidad EAFIT. Departamento de Ciencias; Lógica y Computación
Computación cuántica: una perspectiva desde lo continuo
(Fondo Editorial Universidad EAFIT, 2000-04-01) Sicard, Andrés; Sicard, Andrés; Universidad EAFIT. Departamento de Ciencias; Lógica y Computación
Controlled drug release from a spheroidal matrix
(ELSEVIER SCIENCE BV, 2019-01-01) Simon L.; Ospina J.; Simon L.; Ospina J.; Universidad EAFIT. Departamento de Ciencias; Lógica y Computación
Drug transport through a spheroidal matrix was studied using Fick's second law of diffusion in spherical coordinates. The prolate spheroid-shaped geometry was described by a small angular deformation applied at the surface of the body. An infinite series of Legendre polynomials of order two was first used to develop an expression for the solute concentration in the Laplace domain. This method resulted in closed-form expressions for the effective time constant and the cumulative percentage of drug released in terms of critical model parameters. The procedure predicted published solutions very well. More moisture was observed at the center of the body when compared to the focal point. As the aspect ratio increased, the effective time constant decreased. At 0.38 unit time, 98.6% of the loaded drug was released from the device. © 2018 Elsevier B.V.
Correction of functional logic programs
(SPRINGER, 2003-01-01) Alpuente, M.; Ballis, D.; Correa, F.J.; Falaschi, M.; Alpuente, M.; Ballis, D.; Correa, F.J.; Falaschi, M.; Universidad EAFIT. Departamento de Ciencias; Lógica y Computación
We propose a new methodology for synthesizing correct functional logic programs. We aim to create an integrated development environment in which it is possible to debug a program and correct it automatically. We start from a declarative diagnoser that we have developed previously which allows us to identify wrong program rules w.r.t. an intended specification. Then a bug-correction, program synthesis methodology tries to correct the erroneous components of the wrong code. We propose a hybrid, top-down (unfolding-based) as well as bottom-up (induction-based), approach for the automatic correction of functional logic programs which is driven by a set of evidence examples which are automatically produced as an outcome by the diagnoser. The resulting program is proven to be correct and complete w.r.t. the considered example sets. Finally, we also provide a prototypical implementation which we use for an experimental evaluation of our system. © Springer-Verlag Berlin Heidelberg 2003.
Dealing with Missing Data using a Selection Algorithm on Rough Sets
(ATLANTIS PRESS, 2018-01-01) Prieto-Cubides, J; Argoty, C; Prieto-Cubides, J; Argoty, C; Universidad EAFIT. Departamento de Ciencias; Lógica y Computación
This paper discusses the so-called missing data problem, i.e. the problem of imputing missing values in information systems. A new algorithm, called the ARSI algorithm, is proposed to address the imputation problem of missing values on categorical databases using the framework of rough set theory. This algorithm can be seen as a refinement of the ROUSTIDA algorithm and combines the approach of a generalized non-symmetric similarity relation with a generalized discernibility matrix to predict the missing values on incomplete information systems. Computational experiments show that the proposed algorithm is as efficient and competitive as other imputation algorithms.
A Debugging Scheme of Functional Logic Programs
(Elsevier BV, 2002-01-01) Correa, Francisco Jose; CORREA, FRANCISCO JOSE; Universidad EAFIT. Departamento de Ciencias; Lógica y Computación
Un Depurador Abstracto, Inductivo y Paramétrico Para Programas Multiparadigma
(2004-12-01) Correa, Francisco Jose; CORREA, FRANCISCO JOSE; Universidad EAFIT. Departamento de Ciencias; Lógica y Computación
Deterministic SIR (Susceptible-Infected-Removed) models applied to varicella outbreaks.
(CAMBRIDGE UNIV PRESS, 2008-05-01) Giraldo JO; Palacio DH; Giraldo JO; Palacio DH; Universidad EAFIT. Departamento de Ciencias; Lógica y Computación
Deterministic SIR models were applied to simulate Susceptible-Infected-Removed and to estimate the threshold condition for varicella outbreaks in children, reported in Medellin, Colombia. The expected numbers of susceptible, infected and removed individuals were compared with observed cases from notification of varicella outbreaks to the local Board of Health and from survey data. The threshold condition was estimated by the basic reproductive ratio and by the relative removal rate, through which measures for preventing and curtailing the outbreaks were identified. The model demonstrated a reasonable fit to the observations, except in two of the six outbreaks which probably reflected under-registration of cases. In order to have prevented these outbreaks, between 4.4% and 52.9% of the susceptible population should have been vaccinated assuming an 85% vaccine effectiveness. Similarly, isolation of affected children should have been increased to between 4.3% and 44.8% per week.
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 Computación
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.

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