Antonio Lozano - Academia.edu (original) (raw)
Papers by Antonio Lozano
Boletín de la …, 2007
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Operations Research Letters, 2003
In this paper we address a maximin facility location problem for n points in the plane such that ... more In this paper we address a maximin facility location problem for n points in the plane such that the facility is an anchored line segment of a fixed length. We show how to solve this problem in O(nlogn) time, which is optimal in the algebraic computation tree model. Other variations of this problem are also discussed.
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Que Leer, 2002
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Que Leer, 2006
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... The Visible Structure of Turbulent Jet Diffusion Flames: Large-Scale Organization and Flame T... more ... The Visible Structure of Turbulent Jet Diffusion Flames: Large-Scale Organization and Flame Tip Oscillation MG MUNGAL, PS KARASSO and A LOZANO Mechanical Engineering Department, Stanford University, Stanford, CA 94305-3032 ...
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The planar laser-induced fluorescence (PLIF) technique can be used to instantaneously and non-int... more The planar laser-induced fluorescence (PLIF) technique can be used to instantaneously and non-intrusively record images of concentration, temperature, velocity, and pressure. The technique produces large quantities of data very quickly. These large data sets can be reduced and interpreted using a variety of image processing and graphic projection techniques. In this paper the experimental technique and its resolution are briefly described, and then results are presented for images of the concentration of the molecular tracer biacetyl in a nitrogen jet. Statistical analysis on a series of turbulent jet images yields mean, rms, and dissipation images. A sequence of nine frames of an acoustically forced jet illustrate flow development studies. Finally, eleven images of different cuts through a jet in a crossflow are rendered into three-dimensional iso-concentration contours.
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Results are presented on the structure and mixing of subsonic jets in crossflow. These results ar... more Results are presented on the structure and mixing of subsonic jets in crossflow. These results are obtained by using planar laser-induced fluorescence of acetone vapor which is carried as a marker of the jet fluid. In addition to providing instantaneous realizations of the jet structure, the data is quantitative in providing instantaneous measures of the jet mixture fraction. Jet to
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An optimal line is sought in the Euclidean plane in terms of the ordered median criterion, when t... more An optimal line is sought in the Euclidean plane in terms of the ordered median criterion, when the set of existing facilities are points with arbitrary positive associated weights. By way of geometric duality a dominating set for such a line is found. This allows the construction of an algorithm to solve the problem in O(n 4 ).
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Particle Image Velocimetry (PIV) is becoming a well established experimental technique to measure... more Particle Image Velocimetry (PIV) is becoming a well established experimental technique to measure two components of the velocity in a planar region of a flow field. An experimental method will be described which shows how its proven capabilities can be further extended by using holographic recording to register the particle displacements. Among other unique characteristics, holography enables the acquisition of
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Journal of Mathematical Modelling and Algorithms, 2010
Page 1. J Math Model Algor (2010) 9:117 DOI 10.1007/s10852-009-9119-z The k-Centrum Straight-lin... more Page 1. J Math Model Algor (2010) 9:117 DOI 10.1007/s10852-009-9119-z The k-Centrum Straight-line Location Problem Antonio J. Lozano·Juan A. Mesa·Frank Plastria Received: 2 March 2007 / Accepted: 30 October 2009 ...
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ABSTRACT
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Discrete Applied Mathematics, 2013
ABSTRACT Given a set of weighted points in the plane, a set of non-negative (ordered) weights and... more ABSTRACT Given a set of weighted points in the plane, a set of non-negative (ordered) weights and a connected polygonal region , the weighted anti-ordered median straight-line location problem consists in finding a straight line intersecting and maximizing the sum of ordered weighted distances to the points. In this paper we show how to find such a straight line in time when the Euclidean distance is considered. As a consequence of the results given in the paper the weighted Euclidean anti-median straight-line problem can be solved in time.
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ABSTRACT
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Journal of Power Sources
The flow distribution obtained with three different bipolar plate geometries has been studied, an... more The flow distribution obtained with three different bipolar plate geometries has been studied, analyzing their fluid dynamic performance. Three plate topologies have been selected in some way representative of different design models commonly used. The configurations tested are a set of parallel diagonal channels, a branching cascade type, and a serpentine distribution of parallel channel blocks. The flow distribution across the plates has been first simulated numerically. To visualize the flow pattern at the plate channels plane, a laser-induced fluorescence (LIF) trace tracking technique has been applied. From experimental and numerical simulations it is concluded that the diagonal topology distributes the flow in a non-uniform way. On the other hand, an inadequately large pressure drop is established along the serpentine-parallel plate. In the cascade case, both velocity and pressure fields are very uniform, and it can be expected to produce a very homogeneous distribution of rea...
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Discrete Applied Mathematics, 2013
ABSTRACT In this paper we consider a general model for locating a repulsive facility in a bounded... more ABSTRACT In this paper we consider a general model for locating a repulsive facility in a bounded polygonal region. In order to have a finite set of candidates for the ordered anti-median problem, the class of strictly convex distances must be restricted. For this case an O(sn5)O(sn5) time algorithm is proposed, where ss is an uniform bound on the number of intersections of two bisectors.
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This paper presents time-averaged and temporally evolving mean flow and turbulence statistics for... more This paper presents time-averaged and temporally evolving mean flow and turbulence statistics for a turbulent zero-net-mass-flux (ZNMF) jet at high Reynolds and Strouhal numbers in the far-field in a plane perpendicular to the jet axis. The measurements have been obtained using time-resolved stereo particle image velocimetry (TR-SPIV). The jet is generated by the oscillation of a piston, which discharges filtered water to the quiescent fluid in a tank through a round orifice. A multigrid cross correlation digital particle image velocimetry algorithm (MCCDPIV) has been used to compute the images from each camera that subsequently have been combined to obtain the three components of the velocity. Velocity and turbulence statistics are in good agreement with results obtained in previous work. A comparative study has been performed to determine the contribution to the spreading rate due to the displacement of the center of the jet as rigid body. Different criteria to define the instanta...
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Computers & Operations Research, 2010
ABSTRACT An obnoxious facility is to be located inside a polygonal region of the plane, maximizin... more ABSTRACT An obnoxious facility is to be located inside a polygonal region of the plane, maximizing the sum of the k smallest weighted Euclidean distances to n given points, each protected by some polygonal forbidden region. For the unweighted case and k fixed an O(n2logn) time algorithm is presented. For the weighted case a thorough study of the relevant structure of the multiplicatively weighted order-k-Voronoi diagram leads to the design of an O(kn3+n3logn) time algorithm for finding an optimal solution to the anti-t-centrum problem for every t=1,…,k, simultaneously.
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Bookmarks Related papers MentionsView impact
Boletín de la …, 2007
Bookmarks Related papers MentionsView impact
Operations Research Letters, 2003
In this paper we address a maximin facility location problem for n points in the plane such that ... more In this paper we address a maximin facility location problem for n points in the plane such that the facility is an anchored line segment of a fixed length. We show how to solve this problem in O(nlogn) time, which is optimal in the algebraic computation tree model. Other variations of this problem are also discussed.
Bookmarks Related papers MentionsView impact
Que Leer, 2002
Bookmarks Related papers MentionsView impact
Que Leer, 2006
Bookmarks Related papers MentionsView impact
... The Visible Structure of Turbulent Jet Diffusion Flames: Large-Scale Organization and Flame T... more ... The Visible Structure of Turbulent Jet Diffusion Flames: Large-Scale Organization and Flame Tip Oscillation MG MUNGAL, PS KARASSO and A LOZANO Mechanical Engineering Department, Stanford University, Stanford, CA 94305-3032 ...
Bookmarks Related papers MentionsView impact
The planar laser-induced fluorescence (PLIF) technique can be used to instantaneously and non-int... more The planar laser-induced fluorescence (PLIF) technique can be used to instantaneously and non-intrusively record images of concentration, temperature, velocity, and pressure. The technique produces large quantities of data very quickly. These large data sets can be reduced and interpreted using a variety of image processing and graphic projection techniques. In this paper the experimental technique and its resolution are briefly described, and then results are presented for images of the concentration of the molecular tracer biacetyl in a nitrogen jet. Statistical analysis on a series of turbulent jet images yields mean, rms, and dissipation images. A sequence of nine frames of an acoustically forced jet illustrate flow development studies. Finally, eleven images of different cuts through a jet in a crossflow are rendered into three-dimensional iso-concentration contours.
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Results are presented on the structure and mixing of subsonic jets in crossflow. These results ar... more Results are presented on the structure and mixing of subsonic jets in crossflow. These results are obtained by using planar laser-induced fluorescence of acetone vapor which is carried as a marker of the jet fluid. In addition to providing instantaneous realizations of the jet structure, the data is quantitative in providing instantaneous measures of the jet mixture fraction. Jet to
Bookmarks Related papers MentionsView impact
An optimal line is sought in the Euclidean plane in terms of the ordered median criterion, when t... more An optimal line is sought in the Euclidean plane in terms of the ordered median criterion, when the set of existing facilities are points with arbitrary positive associated weights. By way of geometric duality a dominating set for such a line is found. This allows the construction of an algorithm to solve the problem in O(n 4 ).
Bookmarks Related papers MentionsView impact
Particle Image Velocimetry (PIV) is becoming a well established experimental technique to measure... more Particle Image Velocimetry (PIV) is becoming a well established experimental technique to measure two components of the velocity in a planar region of a flow field. An experimental method will be described which shows how its proven capabilities can be further extended by using holographic recording to register the particle displacements. Among other unique characteristics, holography enables the acquisition of
Bookmarks Related papers MentionsView impact
Journal of Mathematical Modelling and Algorithms, 2010
Page 1. J Math Model Algor (2010) 9:117 DOI 10.1007/s10852-009-9119-z The k-Centrum Straight-lin... more Page 1. J Math Model Algor (2010) 9:117 DOI 10.1007/s10852-009-9119-z The k-Centrum Straight-line Location Problem Antonio J. Lozano·Juan A. Mesa·Frank Plastria Received: 2 March 2007 / Accepted: 30 October 2009 ...
Bookmarks Related papers MentionsView impact
ABSTRACT
Bookmarks Related papers MentionsView impact
Discrete Applied Mathematics, 2013
ABSTRACT Given a set of weighted points in the plane, a set of non-negative (ordered) weights and... more ABSTRACT Given a set of weighted points in the plane, a set of non-negative (ordered) weights and a connected polygonal region , the weighted anti-ordered median straight-line location problem consists in finding a straight line intersecting and maximizing the sum of ordered weighted distances to the points. In this paper we show how to find such a straight line in time when the Euclidean distance is considered. As a consequence of the results given in the paper the weighted Euclidean anti-median straight-line problem can be solved in time.
Bookmarks Related papers MentionsView impact
ABSTRACT
Bookmarks Related papers MentionsView impact
Journal of Power Sources
The flow distribution obtained with three different bipolar plate geometries has been studied, an... more The flow distribution obtained with three different bipolar plate geometries has been studied, analyzing their fluid dynamic performance. Three plate topologies have been selected in some way representative of different design models commonly used. The configurations tested are a set of parallel diagonal channels, a branching cascade type, and a serpentine distribution of parallel channel blocks. The flow distribution across the plates has been first simulated numerically. To visualize the flow pattern at the plate channels plane, a laser-induced fluorescence (LIF) trace tracking technique has been applied. From experimental and numerical simulations it is concluded that the diagonal topology distributes the flow in a non-uniform way. On the other hand, an inadequately large pressure drop is established along the serpentine-parallel plate. In the cascade case, both velocity and pressure fields are very uniform, and it can be expected to produce a very homogeneous distribution of rea...
Bookmarks Related papers MentionsView impact
Discrete Applied Mathematics, 2013
ABSTRACT In this paper we consider a general model for locating a repulsive facility in a bounded... more ABSTRACT In this paper we consider a general model for locating a repulsive facility in a bounded polygonal region. In order to have a finite set of candidates for the ordered anti-median problem, the class of strictly convex distances must be restricted. For this case an O(sn5)O(sn5) time algorithm is proposed, where ss is an uniform bound on the number of intersections of two bisectors.
Bookmarks Related papers MentionsView impact
This paper presents time-averaged and temporally evolving mean flow and turbulence statistics for... more This paper presents time-averaged and temporally evolving mean flow and turbulence statistics for a turbulent zero-net-mass-flux (ZNMF) jet at high Reynolds and Strouhal numbers in the far-field in a plane perpendicular to the jet axis. The measurements have been obtained using time-resolved stereo particle image velocimetry (TR-SPIV). The jet is generated by the oscillation of a piston, which discharges filtered water to the quiescent fluid in a tank through a round orifice. A multigrid cross correlation digital particle image velocimetry algorithm (MCCDPIV) has been used to compute the images from each camera that subsequently have been combined to obtain the three components of the velocity. Velocity and turbulence statistics are in good agreement with results obtained in previous work. A comparative study has been performed to determine the contribution to the spreading rate due to the displacement of the center of the jet as rigid body. Different criteria to define the instanta...
Bookmarks Related papers MentionsView impact
Computers & Operations Research, 2010
ABSTRACT An obnoxious facility is to be located inside a polygonal region of the plane, maximizin... more ABSTRACT An obnoxious facility is to be located inside a polygonal region of the plane, maximizing the sum of the k smallest weighted Euclidean distances to n given points, each protected by some polygonal forbidden region. For the unweighted case and k fixed an O(n2logn) time algorithm is presented. For the weighted case a thorough study of the relevant structure of the multiplicatively weighted order-k-Voronoi diagram leads to the design of an O(kn3+n3logn) time algorithm for finding an optimal solution to the anti-t-centrum problem for every t=1,…,k, simultaneously.
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact