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Papers by Ricardo Vicente

Research paper thumbnail of Study on the criteria for assessing skull-face correspondence in craniofacial superimposition

Legal Medicine, 2016

The version presented here may differ from the published version or from the version of the recor... more The version presented here may differ from the published version or from the version of the record. Please see the repository URL above for details on accessing the published version and note that access may require a subscription.

Research paper thumbnail of A New Forensic Collection housed at the University of Coimbra Portugal: the 21st Century Identified Skeletal Collection

Forensic Science International., 2014

The purpose of this study is to characterize and contextualize the new collection of identified s... more The purpose of this study is to characterize and contextualize the new collection of identified skeletons housed in the Department of Life Sciences at the University of Coimbra, Portugal. The 21 st Century Identified Skeletal Collection, which is still being enlarged, is currently composed of 159 complete adult skeletons (age at death range: 29 to 99 years) of both sexes. The skeletons consist almost exclusively of Portuguese nationals who died between 1995 and 2008. The state of preservation is good and more detailed antemortem information is presently being collected. This collection constitutes a fundamental tool for forensic anthropology research, including development and validation studies of skeletal aging and sexing methods that target elderly adults. Moreover, this collection can also be used in conjunction with the other reference collections housed in the University of Coimbra to investigate secular trends in skeletal development and aging, among others.

Research paper thumbnail of Sex estimation from the tarsal bones in a Portuguese sample: a machine learning approach

International Journal of Legal Medicine, 2014

Sex estimation is extremely important in the analysis of human remains as many of the subsequent ... more Sex estimation is extremely important in the analysis of human remains as many of the subsequent biological parameters are sex specific (e.g., age at death, stature, and ancestry). When dealing with incomplete or fragmented remains, metric analysis of the tarsal bones of the feet has proven valuable. In this study, the utility of 18 width, length, and height tarsal measurements were assessed for sex-related variation in a Portuguese sample. A total of 300 males and females from the Coimbra Identified Skeletal Collection were used to develop sex prediction models based on statistical and machine learning algorithm such as discriminant function analysis, logistic regression, classification trees, and artificial neural networks. All models were evaluated using 10-fold cross-validation and an independent test sample composed of 60 males and females from the Identified Skeletal Collection of the 21st Century. Results showed that tarsal bone sex-related variation can be easily captured with a high degree of repeatability. A simple tree-based multivariate algorithm involving measurements from the calcaneus, talus, first and third cuneiforms, and cuboid resulted in 88.3 % correct sex estimation both on training and independent test sets. Traditional statistical classifiers such as the discriminant function analysis were outperformed by machine learning techniques. Results obtained show that machine learning algorithm are an important tool the forensic practitioners should consider when developing new standards for sex estimation.

Research paper thumbnail of AncesTrees: ancestry estimation with randomized decision trees

International Journal of Legal Medicine, 2014

Research paper thumbnail of AncesTrees: ancestry estimation with randomized decision trees

International Journal of Legal Medicine, Jul 23, 2014

In forensic anthropology, ancestry estimation is essential in establishing the individual biologi... more In forensic anthropology, ancestry estimation is essential in establishing the individual biological profile. The aim of this study is to present a new program—AncesTrees—developed for assessing ancestry based on metric analysis. AncesTrees relies on a machine learning ensemble algorithm, random forest, to classify the human skull. In the ensemble learning paradigm, several models are generated and co-jointly used to arrive at the final decision. The random forest algorithm creates ensembles of decision trees classifiers, a non-linear and non-parametric classification technique. The database used in AncesTrees is composed by 23 craniometric variables from 1,734 individuals, representative of six major ancestral groups and selected from the Howells’ craniometric series. The program was tested in 128 adult crania from the following collections: the African slaves’ skeletal collection of Valle da Gafaria; the Medical School Skull Collection and the Identified Skeletal Collection of 21s...

Research paper thumbnail of Study on the criteria for assessing skull-face correspondence in craniofacial superimposition

Legal Medicine, 2016

The version presented here may differ from the published version or from the version of the recor... more The version presented here may differ from the published version or from the version of the record. Please see the repository URL above for details on accessing the published version and note that access may require a subscription.

Research paper thumbnail of A New Forensic Collection housed at the University of Coimbra Portugal: the 21st Century Identified Skeletal Collection

Forensic Science International., 2014

The purpose of this study is to characterize and contextualize the new collection of identified s... more The purpose of this study is to characterize and contextualize the new collection of identified skeletons housed in the Department of Life Sciences at the University of Coimbra, Portugal. The 21 st Century Identified Skeletal Collection, which is still being enlarged, is currently composed of 159 complete adult skeletons (age at death range: 29 to 99 years) of both sexes. The skeletons consist almost exclusively of Portuguese nationals who died between 1995 and 2008. The state of preservation is good and more detailed antemortem information is presently being collected. This collection constitutes a fundamental tool for forensic anthropology research, including development and validation studies of skeletal aging and sexing methods that target elderly adults. Moreover, this collection can also be used in conjunction with the other reference collections housed in the University of Coimbra to investigate secular trends in skeletal development and aging, among others.

Research paper thumbnail of Sex estimation from the tarsal bones in a Portuguese sample: a machine learning approach

International Journal of Legal Medicine, 2014

Sex estimation is extremely important in the analysis of human remains as many of the subsequent ... more Sex estimation is extremely important in the analysis of human remains as many of the subsequent biological parameters are sex specific (e.g., age at death, stature, and ancestry). When dealing with incomplete or fragmented remains, metric analysis of the tarsal bones of the feet has proven valuable. In this study, the utility of 18 width, length, and height tarsal measurements were assessed for sex-related variation in a Portuguese sample. A total of 300 males and females from the Coimbra Identified Skeletal Collection were used to develop sex prediction models based on statistical and machine learning algorithm such as discriminant function analysis, logistic regression, classification trees, and artificial neural networks. All models were evaluated using 10-fold cross-validation and an independent test sample composed of 60 males and females from the Identified Skeletal Collection of the 21st Century. Results showed that tarsal bone sex-related variation can be easily captured with a high degree of repeatability. A simple tree-based multivariate algorithm involving measurements from the calcaneus, talus, first and third cuneiforms, and cuboid resulted in 88.3 % correct sex estimation both on training and independent test sets. Traditional statistical classifiers such as the discriminant function analysis were outperformed by machine learning techniques. Results obtained show that machine learning algorithm are an important tool the forensic practitioners should consider when developing new standards for sex estimation.

Research paper thumbnail of AncesTrees: ancestry estimation with randomized decision trees

International Journal of Legal Medicine, 2014

Research paper thumbnail of AncesTrees: ancestry estimation with randomized decision trees

International Journal of Legal Medicine, Jul 23, 2014

In forensic anthropology, ancestry estimation is essential in establishing the individual biologi... more In forensic anthropology, ancestry estimation is essential in establishing the individual biological profile. The aim of this study is to present a new program—AncesTrees—developed for assessing ancestry based on metric analysis. AncesTrees relies on a machine learning ensemble algorithm, random forest, to classify the human skull. In the ensemble learning paradigm, several models are generated and co-jointly used to arrive at the final decision. The random forest algorithm creates ensembles of decision trees classifiers, a non-linear and non-parametric classification technique. The database used in AncesTrees is composed by 23 craniometric variables from 1,734 individuals, representative of six major ancestral groups and selected from the Howells’ craniometric series. The program was tested in 128 adult crania from the following collections: the African slaves’ skeletal collection of Valle da Gafaria; the Medical School Skull Collection and the Identified Skeletal Collection of 21s...