Autonomous University of Manizales
Manizales, Colombia
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Tinoco H.A.,Autonomous University of Manizales
International Journal of Fruit Science | Year: 2017

In this study, different approximations are computed for the geometrical and elastic properties of fruits Coffea arabica var. Colombia. By using experimental data of size, volume, and Young’s moduli (semi-experimental), numerical and analytical investigations are carried out to analyze the behavior of these parameters during ripening. Further, new equations are proposed that describe the volume and Young’s modulus in function of the orthogonal diameters ((Formula presented.),(Formula presented.), and (Formula presented.)) and ripening time. The models were in good agreement with the experimental data reported in the literature. Potential applications of the volume model could be explored in in situ identification of the ripening time of the fruits, as well as the evaluation of productivity associated with the studied coffee variety. © 2017 Taylor & Francis

Cardenas P.C.,Autonomous University of Manizales | Teixeira W.S.,Federal University of ABC | Semiao F.L.,Federal University of ABC
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2017

The interaction of qubits with quantized modes of electromagnetic fields has been largely addressed in the quantum optics literature under the rotating wave approximation (RWA), where rapid oscillating terms in the qubit-mode interaction picture Hamiltonian can be neglected. At the same time, it is generally accepted that, provided the interaction is sufficiently strong or for long times, the RWA tends to describe physical phenomena incorrectly. In this work, we extend the investigation of the validity of the RWA to a more involved setup where two qubit-mode subsystems are brought to interaction through their harmonic coordinates. Our treatment is all analytic thanks to a sequence of carefully chosen unitary transformations, which allows us to diagonalize the Hamiltonian within and without the RWA. By also considering qubit dephasing, we find that the purity of the two-qubit state presents non-Markovian features which become more pronounced as the coupling between the modes gets stronger and the RWA loses its validity. In the same regime, there occurs fast generation of entanglement between the qubits, which is also not correctly described under the RWA. The setup and results presented here clearly show the limitations of the RWA in a scenario amenable to exact description and free from numerical uncertainties. Consequently, it may be of interest for the community working with cavity or circuit quantum electrodynamic systems in the strong coupling regime. © 2017 American Physical Society.

Angel-Lopez J.P.,Autonomous University of Manizales | Murillo-Rendon S.,Autonomous University of Manizales
Advances in Intelligent Systems and Computing | Year: 2017

A Markers vision system is a set of infrared cameras capable to distinguish little spheres made of reflective material. These systems usually have been employed to study bio-mechanical processes, and as a tool for animating characters in virtual worlds, for instance in animated movies and video games. In this work, this tool is used as a positioning system for a mobile robot in a closed room. The robot is a prototype made over Arduino®, it consist of a two motor control provided with a proximity sensor for monitoring the space around. The control of this robot was designed to be automatic, in other words it is conditioned to walk in a delimited space and to report the objects found in its way. To control the mobile robot, an algorithmic framework was built in Matlab®. The idea with this framework is to receive the data obtained by the motion capture system to locate the robot in the delimited area. Otherwise, the framework is used to build the virtual map of the place and to produce the control orders to guide the robot. The aim of this work is to evaluate a set of strategies for environment mapping and the performance of the robot in the identification of the hidden space and its reconstruction in a virtual representation. In the other hand, this work is used to teach techniques of artificial vision, algorithm writing, digital signal processing and control to undergraduate students. Furthermore, this project is proposed to identify new lines in mobile robots research and in the development of automatic machines that works in cooperative schemes. © Springer International Publishing AG 2017.

Zimmerman R.D.,Cornell University | Murillo-Sanchez C.E.,Autonomous University of Manizales | Murillo-Sanchez C.E.,National University of Colombia | Thomas R.J.,Cornell University
IEEE Transactions on Power Systems | Year: 2011

Matpower is an open-source Matlab-based power system simulation package that provides a high-level set of power flow, optimal power flow (OPF), and other tools targeted toward researchers, educators, and students. The OPF architecture is designed to be extensible, making it easy to add user-defined variables, costs, and constraints to the standard OPF problem. This paper presents the details of the network modeling and problem formulations used by Matpower, including its extensible OPF architecture. This structure is used internally to implement several extensions to the standard OPF problem, including piece-wise linear cost functions, dispatchable loads, generator capability curves, and branch angle difference limits. Simulation results are presented for a number of test cases comparing the performance of several available OPF solvers and demonstrating Matpower's ability to solve large-scale AC and DC OPF problems. © 2010 IEEE.

Agency: European Commission | Branch: FP7 | Program: CSA | Phase: ICT-2011.3.4 | Award Amount: 466.09K | Year: 2011

The RISC project aims at deepening strategic R&D cooperation between Europe (EU) and Latin America (LA) in the field of High Performance Computing (HPC) by building a multinational and multi-stakeholder community that will involve a significant representation of the relevant HPC R&D EU and LA actors (researchers, policy makers, users). RISC will identify common needs, research issues and opportunities for cooperative R&D on HPC between EU and LA in the transition to multi-core architectures across the computing spectrum and relevant programming paradigms, algorithms and modelling approaches, thus setting the basis for the formulation of a global strategy for future research. The project will achieve its overall aim via a range of activities: 1. Assessing the ICT collaboration potential in the High Performance Computing and Computational Science area for the two regions; producing a Green Paper on High Performance Computing Drivers and Needs in Latin America; mapping the LA HPC actors and trends; identifying the opportunities for LA ICT actors in the EU and for EU HPC actors in LA; aligning EU and LA HPC policies and strategies; 2. Sharing and disseminating information and results in the focus area of EU HPC to a number of research, policy and practice actors dealing with technology applications in the LA region; making available existing Latin American HPC research to EU research, policy and practice actors;\n3.\tOrganising awareness-raising events about the ECs ICT R&D programmes, in particular those ones relevant to HPC and exascale computing for LA HPC actors. Organising Summer Schools and Advanced Workshops between EU and LA ICT actors to inform and initiate research collaborations between them. Networking, capacity building and training components of these events will enhance the impact 4. Actively engaging the relevant industry by focusing on industrial problems and problems with impact for the society. Providing advanced support services to a selected number of competent Latin American ICT actors to build long-term relationships with key EU counterparts. The target areas are: Innovation and HPC and its impact, Mathematical Models enhancing HPC and key areas such as Life Sciences, Climate Change, Financial Modelling etc with the corresponding research clusters concentrated around these areas.\n5.\tExtending HPC with links and relationships with complementary technology and tools in the areas of virtualization, data visualization, data analysis and simulation, aligned with industrial-driven application fields, creating a value chain for final users and practitioners. 6. Enhancing HPC R&D policy dialogue between policy makers and stakeholders from EU and Latin American HPC communities; develop a Road Map towards a Joint Strategy in HPC R&D. At the end of the project we expect a fully functioning network focusing on activities to support and to promote coordination of the HPC and Computational Science research between EU and LA.

Alba-Castro M.,Autonomous University of Manizales
2014 9th Computing Colombian Conference, 9CCC 2014 | Year: 2014

Non-interference is a semantic program property that assigns confidentiality levels to data objects and prevents illicit information flows from high to low security levels. In this paper, we extend a certification technique for confidentiality of Java classes regarding non-interference, in order to consider objects and object aliasing. The technique is based on rewriting logic, which is efficiently implemented in the high-level programming language Maude. Starting from a previous Java abstract semantics specification written in Maude, we develop an information flow sensitive Java semantics that allows us to observe global non-interference properties, with object aliasing. In order to achieve a finite state transition system, we develop an abstract Java semantics that we use for secure and effective confidentiality analysis. We have implemented our methodology and developed some experiments that demonstrate the feasibility of our approach. © 2014 IEEE.

Tinoco H.A.,Autonomous University of Manizales
International Journal of Modeling, Simulation, and Scientific Computing | Year: 2016

In this study, a numerical approach is established to design a beam coupled to a Voice Coil Motor (VCM) with the aim to maximize the displacement in the inductive transducer. A finite element model is developed to simulate a VCM with different beams applying a harmonic analysis. The VCM is extracted from a recycled hard disk drive (HDD) and a parametric modal analysis is performed to identify the material parameters of the HDD and the beam. These parameters are obtained comparing the real vibration modes and natural frequencies (VCM-beam) with those determined from the finite element model. A numerical-experimental case study is carried out to demonstrate that if a beam is designed for a specific low frequency vibration between 0 and 10Hz, the displacements are maximized in the VCM. For this purpose, real acceleration measurements taken from three individuals are used to provide the vibration signals in the numerical model. A beam is designed for one of the individuals using the natural frequency values determined from the measured signals. Results show that the displacements are maximized in the model which coincides with the natural frequency of the chosen individual. The main purpose of this research is to establish a design tool for energy harvesting purposes with VCM based on low frequency vibration sources as for example gait motions. © 2016 World Scientific Publishing Company.

Matas J.,University of Barcelona | Castilla M.,University of Barcelona | De Vicuna L.G.,University of Barcelona | Miret J.,University of Barcelona | And 2 more authors.
IEEE Transactions on Power Electronics | Year: 2010

This paper explores the impact of the output impedance on the active and reactive power flows between parallelized inverters operating with the droop method. In these systems, a virtual output impedance is usually added to the control loop of each inverter to improve the reactive power sharing, regardless of line-impedance unbalances and the sharing of nonlinear loads. The virtual impedance is usually implemented as the time derivative of the inverter output current, which makes the system highly sensitive to the output current noise and to nonlinear loads with high slew rate. To solve this, a second-order general-integrator (SOGI) scheme is proposed to implement the virtual impedance, which is less sensitive to the output current noise, avoids to perform the time derivative function, achieves better output-voltage total harmonic distortion, and enhances the sharing of nonlinear loads. Experimental results with two 2-kVA inverter systems under linear and nonlinear loads are provided to validate this approach. © 2010 IEEE.

Thomson F.,Autonomous University of Manizales
Journal of Agrarian Change | Year: 2011

This article examines connections between Colombia's internal armed conflict and agrarian questions. It pays attention to the country's specific historical trajectory of agrarian change, the violent expression of social tensions that this elicited, and the particular ways in which these dynamics were influenced by a changing global context. This analysis of the intimate ties between violent conflict and agrarian questions in Colombia, both in terms of their historical development and their contemporary manifestations, challenges popular notions of the relationship between armed conflict and development. In particular, the article contributes to a critique of the conventional version of the conflict-development nexus by illustrating ways in which the experience of capitalist development in Colombia has been violent and produced poverty. © 2011 Blackwell Publishing Ltd.

Tinoco H.A.,Autonomous University of Manizales
Structural and Multidisciplinary Optimization | Year: 2016

This study presents a numerical procedure for the analysis of reinforced concrete slabs (RCS) that obey Nielsen’s yield criterion. A pseudo lower bound formulation of finite elements is established to solve the static theorem as a conic optimization problem with the aim to determine the maximum load capacity of RCS. Lower bound solution is improved by means of an adaptive remeshing strategy using a dissipation estimator which is obtained on the normalization of the kinematic criterion defined from the yield criteria. Different known examples are evaluated and the results show a good agreement with the exact values of the collapse load as well as numerical convergence. The displacement rates are estimated from the dual solution established in the optimization problem in order to determine the collapse mechanism in the slab. © 2016 Springer-Verlag Berlin Heidelberg

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