Gustavo Perez - Academia.edu (original) (raw)

Papers by Gustavo Perez

2022 26th International Conference on Pattern Recognition (ICPR)

The exodus of swallows from communal nighttime roosts is often visible as an expanding ring-shape... more The exodus of swallows from communal nighttime roosts is often visible as an expanding ring-shaped pattern in weather radar data. The WSR-88D network operated by the National Weather Service archives more than 25 years of data across 143 stations in the contiguous US. However, access to information about the roosting behavior of swallows is limited by the cost of manual annotation of these scans.We develop an AI system to detect and track swallow roosts in weather radar data. Our model is based on the Faster R-CNN architecture and is customized to incorporate multiple spatial and temporal channels in volumetric radar scans using novel adaptor layers. We systematically study the impact of network architecture and input representation for this task. We incorporate our detection outputs into an AI-assisted system with an interface for human screening to collect research-grade data about roosting behavior. We deploy the system to collect information from 12 radar stations in the Great L...

An analysis of costs and receipts associated with th e produc t ion of manufacturing milk in El V... more An analysis of costs and receipts associated with th e produc t ion of manufacturing milk in El Vigia a r ea of Venezuela was the focus of th is study. A personal in t erview survey of a sample of dairy fa rm operators was cond ucted. Averages for costs, receipts, and net returns were calc ulat ed by size groups. Tabular analysis was used to study relationships between size and other facto r s and net return. Net return pe r cow was positive on the average , but the study indicated a general need for improved levels of produc t ion. Size of operation and capital investment were two factors found to be associated with higher net r eturns.

LatinX in AI at Computer Vision and Pattern Recognition Conference 2021, 2021

We study the problem of improving domain generalization on deep networks by reducing the bias tow... more We study the problem of improving domain generalization on deep networks by reducing the bias towards texture learned by these models when pre-trained in large color image datasets like ImageNet. To do so, we present a style regularization to enforce more shape-biased learning. Also, we propose an experimental setup using synthetically created test sets using state-of the-art style transfer methods. We report our experiments on stylized versions of CIFAR-10 and STL-10 datasets. In our preliminary results presented here, we show that our style regularization improves performance on new domains but not as significantly as with style augmentation.

2019 IEEE International Conference on Smart Computing (SMARTCOMP), 2019

With 40 million amputees living in poor countries with limited access to health care, there is a ... more With 40 million amputees living in poor countries with limited access to health care, there is a significant need for novel prosthetic solutions. This paper presents our preliminary results to develop sustainable prostheses for five upper-extremity amputee patients in Colombia, South America. We utilized a patient-centric methodology, engaging patients at every stage in an effort to increase their satisfaction with their prosthetic and to assess clinical usefulness. We identified patient-specific criteria and compared existing open source hardware systems using the Design Thinking methodology. Finally, we present these data to further the development of myoelectric prosthetics as part of cyber-physical systems.

43 Congreso de la Sociedad Española de Endoscopia Digestiva (Libro de Comunicaciones), 2021

Medical & Biological Engineering & Computing, 2020

Lung cancer is the deadliest cancer worldwide. It has been shown that early detection using low-d... more Lung cancer is the deadliest cancer worldwide. It has been shown that early detection using low-dose computer tomography (LDCT) scans can reduce deaths caused by this disease. We present a general framework for the detection of lung cancer in chest LDCT images. Our method consists of a nodule detector trained on the LIDC-IDRI dataset followed by a cancer predictor trained on the Kaggle DSB 2017 dataset and evaluated on the IEEE International Symposium on Biomedical Imaging (ISBI) 2018 Lung Nodule Malignancy Prediction test set. Our candidate extraction approach is effective to produce accurate candidates with a recall of 99.6%. In addition, our false positive reduction stage classifies successfully the candidates and increases precision by a factor of 2000. Our cancer predictor obtained a ROC AUC of 0.913 and was ranked 1st place at the ISBI 2018 Lung Nodule Malignancy Prediction challenge.

Bulletin de l'Institut de recherches économiques et sociales, 1957

Dans cette étude, on s'est proposé de conjuguer la démographie et la génétique de population.... more Dans cette étude, on s'est proposé de conjuguer la démographie et la génétique de population. Dans le but d'élargir les objectifs de la démographie, quelques modèles mathématiques empruntés à la génétique de population ont été appliqués. Celle-ci se définit en ces termes : « C'est l'ensemble des modèles mathématiques qui peuvent être construits pour représenter l’évolution de la structure d'une population donnée suivant la distribution de ses gènes mendéliens » . Le présent travail n'est qu'un essai, la génétique de population étant une science encore en voie de formation.

Huellas, Jul 30, 2014

El propósito del trabajo de investigación fue abordar, desde una perspectiva geográfica, la dinám... more El propósito del trabajo de investigación fue abordar, desde una perspectiva geográfica, la dinámica territorial del espacio agropecuario pampeano, entendiendo al espacio geográfico como una dimensión de la totalidad social. A partir de una temática de interés para la disciplina se procedió a elaborar el recorte territorial y analizar el caso de una cooperativa regional, conformada en el mes de octubre del año 2009, por un grupo de doce pequeños y medianos productores de la zona de Mauricio Mayer y Colonia Inés y Carlota. Este grupo de chacareros, como ellos mismos se autodenominan, se asociaron con el fin de llevar a cabo un proyecto productivo, que se podría encuadrar desde el análisis del desarrollo rural local, que les permitiese paliar su compleja situación, por su propia condición de tales y, asimismo, promover prácticas tendientes a mejorar sus habilidades en el manejo del rodeo, ante la crisis de la producción ganadera, agravada por la persistente sequía que afectó el último quinquenio de la década de 2000. Para ello, emprendieron estrategias de participación y acciones de intervención directa sobre el territorio, sobre su lugar. Palabras Clave: Cooperativismo, desarrollo rural local, chacareros, territorio, producción ovina. 1 Este artículo se elaboró en el contexto del Proyecto de Investigación "Territorios locales en el mundo actual. Contextos socio-culturales y productivos". Aprobado por Res. N° 170-09-CD-FCH-UNLPam.

Tech Directions, Feb 1, 2013

The airline industry is very competitive, resulting in most U.S. and many international airlines ... more The airline industry is very competitive, resulting in most U.S. and many international airlines being unprofitable. Because of this competition the airlines have been engaging in fare wars (which reduce revenue generated by transporting passengers) while inflation has increased. This situation of course is not developing revenue for the airlines. To revive the airlines to profitability, the difference between revenue received and airline operational cost must be improved. To solve these extreme conditions, the Eightball Express was designed with the main philosophy of developing an aircraft with a low direct operating cost and acquisition cost. Central Coast Designs' (CCD) aircraft utilizes primarily aluminum in the structure to minimize manufacturing cost, supercritical airfoil sections to minimize drag, and fuel efficient engines to minimize fuel burn. Furthermore, the aircraft was designed using Total Quality Management and Integrated Product Development to minimize development and manufacturing costs. Using these primary cost reduction techniques, the Eightball Express was designed to meet the Lockheed/AIAA Request for Proposal (RFP) requirements of a low cost, 153 passenger, 3000 nm. range transport. The Eightball Express is able to takeoff on less than a 7000 ft. runway, cruise at Mach 0.82 at an altitude of 36,000 ft. for a range of 3,000 nm., and lands on a 5,000 ft. runway. lt is able to perform this mission at a direct operating cost of 3.51 cents/available seat mile in 1992 dollars while the acquisition cost is only $28 million in 1992 dollars. By utilizing and improving on proven technologies, CCD has produced an efficient low cost commercial transport for the future.

Journal of colloid and interface science, 2015

Nowadays, there is a wide variety of arsenic decontamination processes being adsorption processes... more Nowadays, there is a wide variety of arsenic decontamination processes being adsorption processes the most efficient. In this concern, superparamagnetic iron oxide nanoparticles (SPION) have been proposed as an appropriate system to improve arsenic adsorption from acidic wastewater. The number of mines, the amount of ore processed, and thus the amount of mine (acid) wastewaters have been rapidly increased in recent decades. For this reason, arsenic removal from contaminated water is an important goal to accomplish environmental regulations. It is noteworthy that aggregation of these nanoparticles has been detected as the main difficulty, hindering the promising adsorption. In order to overcome this drawback, it is proposed a system to avoid aggregation based on nanoparticles dispersion into an appropriate supporting material. To this purpose, SPION have been fixed on a cellulosic sponge achieving a decrease of the aggregation state, an increase of the active centers, and consequentl...

Proceedings. 2004 International Symposium on Empirical Software Engineering, 2004. ISESE '04., 2004

This paper is an experience report on a first attempt to develop and apply a new form of software... more This paper is an experience report on a first attempt to develop and apply a new form of software: a fullservice empirical testbed designed to evaluate alternative software dependability technologies, and to accelerate their maturation and transition into project use. The SCRover testbed includes not only the specifications, code, and hardware of a public safety robot, but also the package of instrumentation, scenario drivers, seeded defects, experimentation guidelines, and comparative effort and defect data needed to facilitate technology evaluation experiments. The SCRover testbed's initial operational capability has been recently applied to empirically evaluate two architecture definition languages (ADLs) and toolsets, Mae and AcmeStudio. The testbed evaluation showed (1) that the ADL-based toolsets were complementary and cost-effective to apply to mission-critical systems; (2) that the testbed was cost-effective to use by researchers; and (3) that collaboration in testbed use by researchers and the Jet Propulsion Laboratory (JPL) project users resulted in actions to accelerate technology maturity and transition into project use. The evaluation also identified a number of lessons learned for improving the SCRover testbed, and for development and application of future technology evaluation testbeds.

Remediation Journal, 2007

Cyclodextrin-enhanced flushing of contaminants from the subsurface is a promising innovative reme... more Cyclodextrin-enhanced flushing of contaminants from the subsurface is a promising innovative remediation technology. It will become more economically viable at more sites if methods can be developed to recover and reconcentrate the cyclodextrin solution after it has been flushed through an aquifer. The goal of this study was to determine if membrane technology is capable of meeting that need. Five membranes with different material properties were tested for this purpose in the laboratory. The results of these tests indicate that there are large differences both in the efficiency of these membranes to extract hydroxpropyl-β-cyclodextrin (HPCD) and their stability when exposed to trichloroethylene (TCE) at concentrations near aqueous solubility. Not only does the molecular weigh cutoff (MWCO) of a membrane determine if HPCD can be retained, but crucial selection criteria are the membrane's resistance and compatibility with TCE. Of the five membrane materials tested, only two (polymer composite membrane and polysulfone) met both these requirements. The polymer composite membrane (MPF-44) showed reliable and stable HPCD recoveries (>95 percent) even when exposed to high TCE concentrations. The polysulfone membrane showed high HPCD recoveries, 88.5 ± 0.4 percent to 97 percent ±1 percent for ultrafiltration and nanofiltration membranes, respectively. However, membrane swelling and deterioration became a problem at high TCE concentrations (>1,000 mg/L). These problems diminished when the TCE concentration was less than 1 mg/L. Field tests demonstrated that batch mode treatment by ultrafiltration doubled the cyclodextrin concentration from 5 to 10 percent within three hours at a constant operating pressure of 13 psi. Under continuous single-pass treatment conditions, cyclodextrin concentration also increased, although the rate of increase was much smaller than in batch mode. Overall, these tests showed that cyclodextrin recovery is possible under field conditions. O