Roberto Leon

Dr. Roberto Leon

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Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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20 January 2022 in Diagnostics
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Journal Article
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CCCésar Cheuque
César Cheuque
MQMARVIN QUERALES
MARVIN QUERALES
RLRoberto Leon
Roberto Leon
RSRodrigo Salas
Rodrigo Salas
Romina TorresRomina Torres
Romina Torres
The evaluation of white blood cells is essential to assess the quality of the human immune system; however, the assessment of the blood smear depends on the pathologist’s expertise. Most machine learning tools make a one-level classification for white blood cell classification. This work presents a two-stage hybrid multi-level scheme that efficiently classifies four cell groups: lymphocytes and monocytes (mononuclear) and segmented neutrophils and eosinophils (polymorphonuclear). At the first level, a Faster R-CNN network is applied for the identification of the region of interest of white blood cells, together with the separation of mononuclear cells from polymorphonuclear cells. Once separated, two parallel convolutional neural networks with the MobileNet structure are used to recognize the subclasses in the second level. The results obtained using Monte Carlo cross-validation show that the proposed model has a performance metric of around 98.4% (accuracy, recall, precision, and F1-score). The proposed model represents a good alternative for computer-aided diagnosis (CAD) tools for supporting the pathologist in the clinical laboratory in assessing white blood cells from blood smear images.

29 July 2016 in Cluster Computing
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GHGonzalo Hernandez
Gonzalo Hernandez
RLRoberto Leon
Roberto Leon
Alejandra UrtubiaAlejandra Urtubia
Alejandra Urtubia

Verified
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RLRoberto Leon
Roberto Leon
JSJorge Soto-Delgado
Jorge Soto-Delgado
EMElizabeth Montero
Elizabeth Montero
MVMatias Isaac Vargas
Matias Isaac Vargas
A semi-exhaustive approach and a heuristic search algorithm use a fragment-based drug design (FBDD) strategy for designing new inhibitors in an in silico process. A deconstruction reconstruction process uses a set of known Hsp90 ligands for generating new ones. The deconstruction process consists of cutting off a known ligand in fragments. The reconstruction process consists of coupling fragments to develop a new set of ligands. For evaluating the approaches, we compare the binding energy of the new ligands with the known ligands.

24 September 2018 in IEEE Intelligent Transportation Systems Magazine
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Journal Article
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CBCarola Alejandra Blazquez
Carola Alejandra Blazquez
JRJana Ries
Jana Ries
Pablo A. Miranda-GonzalezPablo A. Miranda-Gonzalez
Pablo A. Miranda-Gonzalez
RLRoberto Leon
Roberto Leon
Map Matching Algorithms (MMAs) are developed to solve spatial ambiguities that arise in the process of assigning GPS measurements onto a digital roadway network. Scarce systematic parameter tuning approaches exist in the literature for optimizing MMA performance. Thus, a novel framework is proposed for a systematic calibration of the parameters of a post-processing MMA. The calibration approach consists of an Instance-specific Parameter Tuning Strategy (IPTS) that employs Fuzzy Logic principles. The proposed fuzzy IPTS tool determines algorithm-specific parameter values based on instance-specific information a priori to the execution of the MMA. Finally, the proposed IPTS tool is able to adjust to two particular decision maker preferences on algorithm performance, namely solution quality and computational time.

13 April 2020 in Image Analysis and Stereology
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Journal Article
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RLRoberto Leon
Roberto Leon
WNWerner Nagel
Werner Nagel
JOJoachim Ohser
Joachim Ohser
SASteve Arscott
Steve Arscott
Random planar tessellations are presented which are generated by subsequent division of their polygonal cells. The purpose is to develop parametric models for crack patterns appearing at length scales which can change by orders of magnitude in areas such as from nanotechnology, materials science, soft matter, and geology. Using the STIT tessellation as a reference model and comparing with phenomena in real crack patterns, three modifications of STIT are suggested. For all these models a simulation tool, which also yields several statistics for the tessellation cells, is provided in the web. The software is freely available via a link given in the bibliography of this article. The present paper contains results of a simulation study indicating some essential features of the models. Finally, an example of a real fracture pattern is considered which is obtained using the deposition of a thin metallic film onto an elastomer material -- the results of this are compared to the predictions of the model.

17 August 2024 in Mathematics
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RLRoberto Leon
Roberto Leon
Pablo A. Miranda-GonzalezPablo A. Miranda-Gonzalez
Pablo A. Miranda-Gonzalez
Francisco J. Tapia-UbedaFrancisco J. Tapia-Ubeda
Francisco J. Tapia-Ubeda
Elias Olivares-BenitezElias Olivares-Benitez
Elias Olivares-Benitez
This research aims to develop a mathematical model and a solution approach for jointly optimizing a global inventory service level and order sizes for a single-commodity supply chain network with multiple warehouses or distribution centers. The latter face stochastic demands, such as most real-world supply chains do nowadays, yielding significant model complexity. The studied problem is of high relevance for inventory management, inventory location, and supply chain network design-related literature, as well as for logistics and supply chain managers. The proposed optimization model minimizes the total costs associated with cycle inventory, safety stock, and stock-out-related events, considering a global inventory service level and differentiated order sizes for a fixed and known set of warehouses. Subsequently, the model is solved by employing the Newton–Raphson algorithm, which is developed and implemented assuming stochastic demands with a normal approximation. The algorithm reached optimality conditions and the convergence criterion in a few iterations, within less than a second, for a variety of real-world sized instances involving up to 200 warehouses. The model solutions are contrasted with those obtained with a previous widely employed approximation, where safety stock costs were further approximated and order sizes were optimized without considering stock-out-related costs. This comparison denotes valuable benefits without significant additional computational efforts. Thus, the proposed approach is suitable for managers of real-world supply chains, since they would be able to attain system performance improvements by simultaneously optimizing the global inventory service level and order sizes, thereby providing a better system cost equilibrium.