Papers by Fernando Mendoza
Introduction: The Alagille Syndrome is an autosomic dominant disorder with variable expression. C... more Introduction: The Alagille Syndrome is an autosomic dominant disorder with variable expression. Chronic cholestasis, characteristic facial appearance and abnormalities heart, skeleton, eye, kydnes with hypoplasia of the biliary ducts. Initial description in France, with mundial distribution her frecuence is 1/100000. Objective: To describe the clinical characteristic and evolutions of fourteen patients with diagnosis Alagille Syndrome in Medellín Colombia. Materials and methods: Descriptive retrospective study with variables obtained from clinical records of patients with diagnosis Alagille Syndrome. Results: Eight boys and six girls. The age at diagnosis varied two months at nine years. Complete syndrome was present in 28%. The most frecuent alterations were valvular stenosis pulmonary artery and failure of anterior vertebral arch fusion (butterfly vertebrae) 79%. The clinical evolution was variable, death occurred in three patients 21%, one girl post liver transplantation. Nine children had chronic hepatopathy controlled with medical treatment and two girls had liver transplantation with satisfactory evolution. Conclusions: In Colombia, the poblational incidence is not defined it is necessary to know the distribution of syndrome at future study.
Revista Latinoamericana De Educacion Inclusiva, 2014
El presente trabajo expone una investigación mixta de tipo descriptiva cuyo principal objetivo fu... more El presente trabajo expone una investigación mixta de tipo descriptiva cuyo principal objetivo fue conocer las características profesionales para la atención a
Food Engineering Series, 2015
Image analysis is used as a fundamental tool for recognizing, differentiating, and quantifying di... more Image analysis is used as a fundamental tool for recognizing, differentiating, and quantifying diverse types of images, including grayscale and color images, multispectral images for a few discrete spectral channels or wavebands (normally less than 10), and hyperspectral images with a sequence of contiguous wavebands covering a specific spectral region (e.g., visible and near-infrared). Earlier works on image analysis were primarily confined to the computer science community, and they mainly dealt with simple images for such applications as defect detection, segmentation and classification. Nowadays, image analysis is becoming increasingly important and widespread because it can be done more conveniently, rapidly and cost effectively (Prats-Montalban et al. 2011). Image analysis relies heavily on machine vision technology (Aguilera and Stanley 1999). The explosive growth in both hardware platforms and software frameworks has led to significant advances in the analysis of digital images.
13th World Congress of Food Science & Technology, 2006
The success of controlled atmosphere storage of fruit critically depends on the gas composition o... more The success of controlled atmosphere storage of fruit critically depends on the gas composition of the storage atmosphere. Gas transport models can be used advantageously to evaluate the effect of gas composition on product quality and to optimise and control the storage process. In this paper we will discuss gas and moisture transport models of increasing complexity. We will focus on recent advances in multiscale transport models. Such models are basically a hierarchy of models which describe the transport phenomena at different spatial scales in such a way that the submodels are interconnected. We will pay particular attention to methods to measure product topology and material properties at the micro-and nanoscale.
13th World Congress of Food Science & Technology, 2006
Modeling plant microstructure is of great interest to food engineers to simulate the behavior of ... more Modeling plant microstructure is of great interest to food engineers to simulate the behavior of the physical properties (e.g., concerning mass transfer, mechanics) of plant tissues at the cellular level. The generation of geometrical models of microscopic structures is considered a prime requirement to develop microscale models to study and describe these properties. For this end, this paper presents a novel ellipse tessellation algorithm to generate a 2D geometrical model of apple tissue. Ellipses are used to quantify the orientation and aspect ratio of cells on a microscopic image. The cell areas and centroids of each cell are also determined by means of a numerical procedure. These characteristic quantities are then described by means of probability density functions. The model tissue geometry is generated from the ellipses which are truncated when neighboring areas overlap. As a result, a virtual microstructure consisting of truncated ellipses fills up the entire space with the same number of cells as that of microscopic images and with similar area, orientation and aspect ratio distribution. The spatial variability of the geometric characteristics (cell area size, cell shape, cell orientation and tissue porosity) of the virtual cellular structure was also evaluated and compared to that of the microscopic images. Statistical analysis showed that the virtual geometry generated with this approach yields spatially equivalent geometries to that of real fruit microstructures. Compared to the more common algorithm of Voronoi diagrams, ellipse tesselation is superior for generating the microstructure of tissue. The extension of the algorithm to 3D is straightforward. These representative tissues will be exported into a finite element environment via interfacing codes to perform in silico experiments for estimating gas and moisture diffusivities and investigating their relation with fruit microstructure.
13th World Congress of Food Science & Technology, 2006
Gas filled intercellular spaces are considered the predominant pathways for gas transport through... more Gas filled intercellular spaces are considered the predominant pathways for gas transport through plant organs and, as such, are greatly related to the characteristics of gas exchange. To understand the transport mechanisms of gas diffusion of fruit tissue, a microscale model for the transport of O 2 in the intercellular spaces, the cell wall network and the intracellular liquid phase was introduced. The objective of this study was (1) to verify the applicability of the microscale model of the gas transport at tissue level and (2) to quantify the pathways of gas transport in relation to the microstructure of fruit tissue. The 2D microstructure of pear tissue was modelled from light microscopy images using the ellipse tessellation method. Gas transport properties of the gas and liquid phases and the cell membrane were determined from available literature data. The O 2 transfer in each of intercellular space, cell wall and cytoplasm was applied using diffusion laws and irreversible thermodynamics. The model was solved using the finite element method. The results showed that the microscale model can be applied to study the gas transport in fruit tissue. The model quantified the pathways of gas transport in fruit tissue. The O 2 transport was mainly by means of the intercellular space, the cell wall network and less through the intracellular liquid. The results have important consequences for respiration-related disorders of fruits.
V International Postharvest Symposium, 2005
A computer vision system was implemented to predict the ripening stages of bananas. Our objective... more A computer vision system was implemented to predict the ripening stages of bananas. Our objective was to develop a computer vision algorithm to predict the seven ripening stages based on previously graded bananas by expert visual inspection. Two simple colour features from each image (mean value and variance of the intensity histogram of image) were extracted and analyzed using the RGB, HSV and CIELAB colour spaces with classification purposes. The classification performance of three colour sets of features were compared using discriminant analysis as selection criteria: (1) using colour data extracted from full image of the bananas; (2) colour data from the background of the bananas free of spots (BFS); and (3) combination of the colour data extracted separately from the BFS and brown spots of the banana. Results show that the three evaluated sets were able to correctly predict with more than 94% of accuracy the ripening stages of bananas. The inclusion of colour features from images of brown spots improves the resolution of the classification performance, in particular for stages 4 and 5. In addition, this technique can be extended to evaluate the different quality classes according to the standards proposed by the Codex Alimentaria. Computer vision shows promise as a non-destructive method for on-line prediction of ripening stages of bananas.
Revista de la Facultad de Medicina, 2015
Background. An exponential law for chaotic cardiac dynamics, found previously, allows the quantif... more Background. An exponential law for chaotic cardiac dynamics, found previously, allows the quantification of the differences between normal cardiac dynamics and those with acute diseases, as well as the cardiac dynamics of the evolution between these states. Objective. To confirm the clinical applicability of the developed methodology through the mathematical law for cardiac dynamics in dynamics with arrhythmias. Materials and methods. 60 Holter electrocardiograms were analyzed, 10 corresponded to normal subjects, and 50 to subjects with different arrhythmias. For each Holter, an attractor was performed, and its fractal dimension and spatial occupancy were measured. A mathematical evaluation was applied in order to differentiate normal dynamics from pathological ones. Sensitivity, specificity and the Kappa coefficient were calculated. Results. The mathematical evaluation differentiated occupation spaces, normal dynamics, acute illness dynamics, and evolution between these states. The sensitivity and specificity values were 100%, and the Kappa coefficient was 1. Conclusions. The clinical applicability of the methodology for cases with arrhythmia was shown. It is also applicable for the detection of changes in dynamics that are not classified clinically as pathological.
Postharvest Biology and Technology, 2015
The objective of this research was to evaluate the changes of optical absorption and scattering p... more The objective of this research was to evaluate the changes of optical absorption and scattering properties in tomatoes during ripening, and develop classification models for grading the ripeness of tomatoes using optical absorption and scattering spectra. Optical absorption (m a) and reduced scattering (m s 0) coefficients over the spectral region between 500 nm and 950 nm were measured, using a hyperspectral imaging-based spatially-resolved instrument, for 281 'Sun Bright' tomatoes harvested at six ripeness grades (i.e., 'Green', 'Breaker', 'Turning', 'Pink', 'Light-red', 'Red'). Absorption peak around 675 nm decreased consistently with the progression of ripeness, and its mean value for 'Red' tomatoes was almost zero. The reduced scattering spectra, on the other hand, decreased monotonically with the increasing wavelength; the value of m s 0 also decreased successively from 'Green' to 'Turning', and an opposite trend was observed from 'Pink' to 'Red'. Partial least squares discriminant analysis (PLS-DA) models yielded 92.1%, 84.4%, 92.3%, and 92.1% classification accuracies for the three ripeness grades (i.e., 'Green/Breaker', 'Turning/Pink', and 'Light-red/Red'), when using the full spectra (500-950 nm) of m a ,m s 0 , m a &m s 0 and the effective attenuation coefficient (m eff = [3m a (m a + m s 0)] 1/2), respectively. The PLS-DA model using m eff achieved an overall classification accuracy of 88.4% for the six ripeness grades, which was 2.5% and 10.2% better than using the optical parameters of m a and m s 0 alone. The research demonstrated that the optical absorption and scattering spectra, especially their combinations, are effective for classification of tomato ripeness. 2015 Elsevier B.V. All rights reserved.
2011 Louisville, Kentucky, August 7 - August 10, 2011, 2011
ABSTRACT Visible/near-infrared (VNIR) spectroscopy and spectral scattering are based on different... more ABSTRACT Visible/near-infrared (VNIR) spectroscopy and spectral scattering are based on different sensing principles, and they have shown different abilities for predicting apple fruit firmness and soluble solids content (SSC). Hence the two techniques could work synergistically to improve the quality prediction of apples. In this research, VNIR spectroscopic and spectral scattering data for the wavelength range of 460–1,100 nm were collected for 6,631 apples of ‘Delicious', 'Golden Delicious' and 'Jonagold' cultivars during the 2009 and 2010 harvest seasons and for three months after the refrigerated air storage. Partial least squares models were developed for each sensor and their combination to predict the fruit firmness and SSC for both single-year and cross-year data sets. The spectral scattering technique generally performed better in predicting firmness, whereas the VNIR technique was superior for prediction of SSC. Overall, the data fusion of the two sensors produced significant improvements (p
Postharvest Biology and Technology, 2012
Four nondestructive technologies (i.e., acoustic firmness, bioyield firmness, visible and shortwa... more Four nondestructive technologies (i.e., acoustic firmness, bioyield firmness, visible and shortwave near infrared (Vis-SWNIR) spectroscopy, and spectral scattering) have been developed in recent years for assessing the firmness and/or soluble solids content (SSC) of apples. Each of these technologies has its merits and limitations in predicting the two quality parameters. With the concept of multi-sensor data fusion, different sensors would work synergistically and complementarily to improve the quality prediction of apples. In this research, the four sensing systems were evaluated and combined for nondestructive prediction of the firmness and SSC of 'Jonagold' (JG), 'Golden Delicious' (GD), and 'Delicious' (RD) apples. A total of 6535 apples harvested in 2009 and 2010 were used for analysis. Better predictions of the firmness and, in most cases, of the SSC were obtained using sensors fusion than using individual sensors, as measured by correlation coefficient and standard error of prediction (SEP). The SEPs for the firmness of JG, GD and RD using the best combination of two-sensor data were reduced by 13.5%, 20.0% and 7.3% for the 2009 data and 14.6%, 14.2% and 6.2% for the 2010 data; and using the best three or four fused sensor data by 19.1%, 24.9% and 13.9% in 2009, and 15.7%, 23.6%, and 8.9% in 2010, respectively. The combination of Vis-SWNIR and scattering data improved SSC predictions for RD apples, with the SEP values being reduced by 5.8% and 6.0% for 2009 and 2010, respectively. This research demonstrated that the fused systems provided more complete and complementary information and, thus, were more effective than individual sensors in prediction of apple quality.
Theoretical and Applied Genetics, 2015
Kernel and ear traits are key components of grain yield in maize (Zea mays L.). Investigation of ... more Kernel and ear traits are key components of grain yield in maize (Zea mays L.). Investigation of these traits would help to develop high-yield varieties in maize. Genomewide association study (GWAS) uses the linkage disequilibrium (LD) in the whole genome to determine the genes affecting certain phenotype. In this study, five ear traits (kernel length and width, ear length and diameter, cob diameter) were investigated across multi-environments for 2 years. Combining with the genotype obtained from Maize SNP50 chip, genetic diversity and association mapping in a set of 292 inbred lines were performed. Results showed that maize lines were clustered into seven subgroups and a total of 20 SNPs were found to be associated with ear traits significantly (P < 3.95E-05). The candidate genes identified by GWAS mainly encoded ubiquitin-activation enzymes (GRMZM2G015287), carotenoid cleavage dioxygenase (GRMZM2G446858), MYB-CC type transfactor, and phosphate starvation response protein 3, and they were associated with kernel length (KL) and ear diameter (ED), respectively. Moreover, two novel genes corresponding to RNA processing and fructose metabolism were found. Further, the SNPs detected by GWAS were confirmed by meta-QTL analysis. These genes and SNPs identified in the study would offer essential information for yield-related genes clone and breeding program in maize.
Journal of Surgical Research, 2015
Ingested foreign bodies are a frequent presentation in pediatric emergency departments. Although ... more Ingested foreign bodies are a frequent presentation in pediatric emergency departments. Although some pass spontaneously through the gastrointestinal tract, the majority of esophageal-ingested foreign bodies (EFB) require removal. Kids&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; Inpatient Database (1997-2009) was used to identify children (aged &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;20 y) with EFB (International Classification of Diseases, Ninth Revision, Clinical Modification code 935.1). Multivariate logistic regression analyses were constructed to identify predictors of resource utilization. Overall, 14,767 EFB cases were identified. Most patients were &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;5 y of age (72%), boys (57%), and non-Caucasian (55%), with a median (interquartile range) length of stay (LOS) of 1 (1) d, and total charges of $11,003 (8503). A total of 11,180 procedures were performed, most commonly esophagoscopy (77%), followed by bronchoscopy (20%), gastroscopy (2%), and rarely surgery (0.8%). By multivariate logistic regression, increased total charges were associated with a diagnosis of esophageal ulceration (odds ratio [OR] = 1.57), esophagoscopy (OR = 1.42), and bronchoscopy (OR = 1.62), all P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001. Total charges also increased with admission to urban…
Transactions of the ASABE, 2012
The objective of this research was to measure the spectral absorption (µ a) and reduced scatterin... more The objective of this research was to measure the spectral absorption (µ a) and reduced scattering coefficients (µ s ') of peaches, using a hyperspectral imaging-based spatially resolved method, for maturity/quality assessment. A newly developed optical property measuring instrument was used for acquiring hyperspectral reflectance images of 500 'Redstar' peaches. The µ a and µ s ' spectra for 515 to 1,000 nm were extracted from the spatially resolved reflectance profiles using a diffusion model coupled with an inverse algorithm. The absorption spectra of peach fruit were marked with absorption peaks around 525 nm for anthocyanin, 620 nm for chlorophyll-b, 675 nm for chlorophyll-a, and 970 nm for water, while µ s ' decreased monotonically with the increasing wavelength for most of the tested samples. Both µ a and µ s ' were correlated with peach firmness, soluble solids content (SSC), and skin and flesh color parameters. Better correlation results for partial least squares models were obtained using the combined values of µ a and µ s ' (i.e., µ a × µ s ' and µ eff) than using µ a or µ s ', where µ eff is the effective attenuation coefficient: µ eff = [3µ a (µ a + µ s ')] 1/2. The results were further improved using least squares support vector machine models, with values of the best correlation coefficient for firmness, SSC, skin lightness, and flesh lightness being 0.749 (standard error of prediction or SEP = 17.39 N), 0.504 (SEP = 0.92 °Brix), 0.898 (SEP = 3.45), and 0.741 (SEP = 3.27), respectively. These results compared favorably to acoustic and impact firmness measurements, whose correlations with destructive measurements were 0.639 and 0.631, respectively. The hyperspectral imaging-based spatially resolved technique is useful for measuring the optical properties of peach fruit, and it has good potential for assessing fruit maturity/quality attributes.
2013 Kansas City, Missouri, July 21 - July 24, 2013, 2013
Abstract. Visible and near-infrared (Vis-NIR) spectroscopy is a promising technique for noninvasi... more Abstract. Visible and near-infrared (Vis-NIR) spectroscopy is a promising technique for noninvasive measurement of quality attributes of agricultural products. The technique relies on selection or extraction of optimal spectral features or wavelengths for the development of calibration models. Five wavelengths selection algorithms, namely, uninformative variable elimination (UVE), partial least squares projection analysis (PLSPA), standard genetic algorithm (SGA), successive projections algorithm (SPA), and affinity propagation (AP), were investigated for extracting optimal wavelengths from the spectra of 460 - 1,100 nm to evaluate their ability for prediction of firmness and soluble solids content (SSC) in apples using partial least squares (PLS) method. More than 6,500 apples of ‘Delicious’, ‘Golden Delicious’ and ‘Jonagold’ varieties harvested in 2009 and 2010 were used for analysis. Overall, the prediction results from each wavelength selection algorithm were not as good as those obtained by full-spectrum PLS models. A simple fusion method, which averaged over the prediction results from the five wavelengths selection algorithms, improved prediction results for firmness and SSC by 0.4%-4.8% and 0.4-5.6%, respectively, compared with the full-spectrum PLS models for the three varieties of apples. This fusion method provides a simple and robust means for improving firmness and SSC prediction results.
2013 Kansas City, Missouri, July 21 - July 24, 2013, 2013
ABSTRACT Hyperspectral imaging is useful for detecting internal defects of pickling cucumbers. Th... more ABSTRACT Hyperspectral imaging is useful for detecting internal defects of pickling cucumbers. The technique, however, is not yet suitable for high-speed online implementation due to the challenges in analyzing large-scale hyperspectral images. This research aimed to select the optimal wavebands from the hyperspectral image data, so that they can be deployed in either a hyperspectral or multispectral imaging-based inspection system for the automatic detection of internal defects of pickling cucumbers. Hyperspectral reflectance (400–700 nm) and transmittance (700–1,000 nm) images were acquired, using an in-house developed hyperspectral imaging system running at two conveyor speeds of 85 and 165 mm/s, for 300 “Journey” pickling cucumbers before and after internal damage was induced by mechanical load. Minimum redundancy–maximum relevance (MRMR) was used for optimal wavebands selection, and the loadings of principal component analysis (PCA) were also applied for qualitatively identifying the important wavebands that are related to the specific features. Discriminant analysis with Mahalanobis distance classifier was performed for the two-class (i.e., normal and defective) and three-class (i.e., normal, slightly defective, and severely defective) classifications using the mean spectra and textural features (energy and variance) from the regions of interest in the spectral images at selected waveband ratios. The classification results based on MRMR wavebands selection were generally better than those from PCA-based classifications. The two-band ratio of 887/837 nm from MRMR gave the best overall classification results, with the accuracy of 95.1 and 94.2 % at the conveyor speeds of 85 and 165 mm/s, respectively, for the two-class classification. The highest classification accuracies for the three-class classification based on the optimal two-band ratio of 887/837 nm were 82.8 and 81.3 % at the conveyor speeds of 85 and 165 mm/s, respectively. The mean spectra-based classification achieved better results than the textural feature-based classification, except in the three-class classification for the higher conveyor speed. The overall classification accuracies for all selected waveband ratios at the low conveyor speed were slightly higher than those at the higher conveyor speed, since the low speed resulted in more scan lines, thus higher spatial resolution hyperspectral images. The identified two-band ratio of 887/837 nm in transmittance mode could be applied for fast real-time internal defect detection of pickling cucumbers.
2013 Kansas City, Missouri, July 21 - July 24, 2013, 2013
Abstract. Spectral scattering is useful for nondestructive sensing of fruit firmness. Prediction ... more Abstract. Spectral scattering is useful for nondestructive sensing of fruit firmness. Prediction models, however, are typically built using multivariate statistical methods such as partial least squares regression (PLSR), whose performance generally depends on the characteristics of the data. The aim of this research was to evaluate the influence of range of variability for Magness-Taylor firmness data (i.e., number of samples at 100%, 80% and 60% of the total variability), preprocessing method [mean reflectance and continuous wavelet transform (CWT) decomposition], and harvest season (2009 and 2010) on the performance and robustness of the calibration models for predicting the firmness of 'Jonagold', ‘Golden Delicious', and 'Delicious' apples. A 3A—2 2 mixed factorial experimental design with six replicates per run was used for assessing PLSR models for the spectral scattering data. The same prediction set of apple samples for each replication was tested for the models. The main effects and interactions for the three variables, and their polynomial models were calculated based on the number of latent variables needed for the model building and the standard error of prediction (SEP). Overall results showed that models using large datasets needed a larger number of latent variables and produced smaller SEP values than the small sample dataset models for all apple cultivars. Models preprocessed by mean reflectance method resulted in a smaller number of variables than the models preprocessed by CWT. The results also demonstrated that increasing the number of samples used in the calibration set resulted in decreases in the SEP, although the largest decrease was observed between 350 and 400 samples. It is, therefore, recommended that the number of samples be chosen according to the accuracy required, although 400 apple samples was considered appropriate in this study to establish calibration models for firmness with lower prediction errors.
The relative proportions of the lower extremities and trunk in American Black, non-Hispanic Ameri... more The relative proportions of the lower extremities and trunk in American Black, non-Hispanic American White, and Mexican American children and youth 2 through 17 years of age are compared. The data for the Blacks and Whites are derived from NHANES II, while those for the Mexican Americans are derived from HHANES. Mean sitting height/stature ratios indicate only small differences in the proportion of lower extremity length to stature in Mexican American and non-Hispanic White children and youth, while Blacks have proportionately longer lower extremities. The same trend is evident when leg length is plotted relative to stature. The shorter lower extremities of Mexican American youth are, to a large extent, a function of their shorter statures. Regression analyses suggest that poverty status is related to length measurements (stature, sitting height, leg length) but not to relative proportions, and that poverty status is a significant factor only during early and middle childhood. There are no associations in adolescence between poverty and any of the anthropometric characteristics studied
SPIE Proceedings, 2011
ABSTRACT Several nondestructive technologies have been developed for assessing the firmness and s... more ABSTRACT Several nondestructive technologies have been developed for assessing the firmness and soluble solids content (SSC) of apples. Each of these technologies has its merits and limitations in predicting the two quality parameters. With the concept of multi-sensor data fusion, different sensors would work synergistically and complementarily to improve the quality prediction of apples. In this research, four sensing systems (i.e., an acoustic sensor, a bioyield firmness tester, a miniature near-infrared (NIR) spectrometer, and an online hyperspectral scattering system) were evaluated and combined for nondestructive prediction of firmness and SSC of &#39;Jonagold&#39; (JG), &#39;Golden Delicious&#39; (GD), and &#39;Delicious&#39; (RD) apples. A total of 6,535 apples harvested in 2009 and 2010 were used for analysis. Each of the four sensors showed various degrees of ability to predict apple quality. Better predictions of the firmness and, in most cases, of the SSC were obtained using sensors fusion than using individual sensors, as measured by number of latent variables, correlation coefficient, and standard error of prediction (SEP). Results obtained from the two harvest seasons with the multi-sensor fusion approach were quite consistent, confirming the validity and robustness of the proposed approach. The SEPs for firmness measurement of JG, GD and RD using the best combination of two-sensor data were reduced by 13.3, 19.7 and 7.9% for the 2009 data and 16.0, 12.6 and 4.7% for the 2010 data; and using all four-sensor data by 21.8, 25.6 and 13.6% in 2009, and 14.9, 21.9, and 7.9% in 2010, respectively. For SSC prediction, using the two-sensor data (i.e., NIR and scattering) improved predictions for JG, GD and RD apples harvested in 2009, with their SEP values being reduced by 10.4, 6.6 and 6.8%, respectively. This research demonstrated that the fused systems provided more complete complementary information and, thus, were more powerful than individual sensors in prediction of apple quality.
Communications in agricultural and applied biological sciences, 2006
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Papers by Fernando Mendoza