Global Sensitivity Estimates for Neural Network Classifiers Fernandez-Navarro, Francisco; Carbonero-Ruz, Mariano; Becerra Alonso, David ...
IEEE transaction on neural networks and learning systems,
11/2017, Letnik:
28, Številka:
11
Journal Article
Artificial neural networks (ANNs) have traditionally been seen as black-box models, because, although they are able to find "hidden" relations between inputs and outputs with a high approximation ...capacity, their structure seldom provides any insights on the structure of the functions being approximated. Several research papers have tried to debunk the black-box nature of ANNs, since it limits the potential use of ANNs in many research areas. This paper is framed in this context and proposes a methodology to determine the individual and collective effects of the input variables on the outputs for classification problems based on the ANOVA-functional decomposition. The method is applied after the training phase of the ANN and allows researchers to rank the input variables according to their importance in the variance of the ANN output. The computation of the sensitivity indices for product unit neural networks is straightforward as those indices can be calculated analytically by evaluating the integrals in the ANOVA decomposition. Unfortunately, the sensitivity indices associated with ANNs based on sigmoidal basis functions or radial basis functions cannot be calculated analytically. In this paper, the indices for those kinds of ANNs are proposed to be estimated by the (quasi-) Monte Carlo method.
Abstract
Motivation
Protein folding is a dynamic process through which polypeptide chains reach their native 3D structures. Although the importance of this mechanism is widely acknowledged, very few ...high-throughput computational methods have been developed to study it.
Results
In this paper, we report a computational platform named P3Fold that combines statistical and evolutionary information for predicting and analyzing protein folding routes. P3Fold uses coarse-grained modeling and efficient combinatorial schemes to predict residue contacts and evaluate the folding routes of a protein sequence within minutes or hours. To facilitate access to this technology, we devise graphical representations and implement an interactive web interface that allows end-users to leverage P3Fold predictions. Finally, we use P3Fold to conduct large and short scale experiments on the human proteome that reveal the broad conservation and variations of structural intermediates within protein families.
Availability and implementation
A Web server of P3Fold is freely available at http://csb.cs.mcgill.ca/P3Fold.
Supplementary information
Supplementary data are available at Bioinformatics online.
Based on the notion of événement (event), elaborated by the French philosopher Alain Badiou, this essay aims to offer a definition of the 15M movement as an event. According to Badiou, the event has ...the capacity to perforate established knowledge and to transform the codes of communication. The event destabilizes the regime of truth to the extent that what was assumed to be obvious now appears as unstable, and, consequently, the need arises to explore and construct other discourses capable of naming the new situation. In this essay, I locate two moments of the event: the political moment and the theoretical moment; the first is the time of the revolution, while the second is devoted to the study and theorization of this revolution. I argue that the radical effects of the event can be registered in the second moment. In the theoretical moment, there is a crisis of the organic intellectuals of the Regime of ’78, and the empty space they leave behind may begin to be occupied by other voices that were previously barely heard. In the same way, during the theoretical moment, the revolution without a genealogical tree that was the 15M, which was not inscribed in a revolutionary continuity, begins to seek its roots in discourses of the past that were silenced or forgotten, or that simply did not have a framework that would give them back their conditions of legibility.
The growing establishment of port structures in estuarine regions has resulted in alternated sedimentation patterns and new geoforms. The primary purpose of this study is to understand the recent ...formation and geomorphological evolution of the fluvial bar in the final portion of the Magdalena River. The geomorphological evolution analysis was made possible using Geographic Information Systems tools, satellite images, and bathymetric data. The studied bar formed and stabilized through anthropic and natural factors such as port structures (obstacles to sediment transport), channel morphology, and natural- and anthropic-caused variation to the sediment supply. The lateral bar formation, adjacent to port structures, began in 2017 with surface runoff accumulating and anchored on the riverbank since 2018. At present, the bar covers 45% of the original river width, and an approximate sediment volume worth 4,000,000 m3 has accumulated. Changes in the navigable channel result in slope modification from 2.02° to 5.36°. The construction of port structures, i.e. new pile bridges, changes the natural sediment flow, because they are obstacles, trapping sediments downstream. This period coincides with the end of a weak El Niño cycle, subsequent to a La Nina period also of low intensity, with reduced precipitation rates resulting in a decrease in flow, and therefore contributing to an increase in sedimentation. The observations suggest that it is crucial to understand the channel bars' morphology and origin to avoid possible economic and social impacts due to the disruptions in navigation.
•Bar stabilized in the Magdalena River by anthropic/natural factors.•Rigid structures will result in changes on the hydro-sedimentary equilibrium.•Growth of bars in the Magdalena River estuary results in limiting navigable channel.•Damage in the port of Barranquilla due to the narrowing of the navigable channel.
Purpose
To compare the short-term and oncologic outcomes of patients with pancreatic ductal adenocarcinoma (PDAC) undergoing laparoscopic distal pancreatectomy (LDP) and open distal pancreatectomy ...(ODP).
Methods
Consecutive cases of distal pancreatectomy (DP) (
n
= 422) were reviewed at a single high-volume institution over a 10-year period (2005–2014). Inclusion criteria consisted of any patient with PDAC by surgical pathology. Ninety-day outcomes were monitored through a prospectively maintained pancreatic resection database. The Social Security Death Index was used for 5-year survival. Two-way statistical analyses were used to compare categories; variance was reported with standard error of the mean; * indicates
P
value <0.05.
Results
Seventy-nine patients underwent DP for PDAC. Thirty-three underwent LDP and 46 ODP. There were no statistical differences in demographics, BMI, and ASA classification. Intraoperative and surgical pathology variables were comparable for LDP versus ODP: operative time (3.9 ± 0.2 vs. 4.2 ± 0.2 h), duct size, gland texture, stump closure, tumor size (3.3 ± 0.3 vs. 4.0 ± 0.4 cm), lymph node harvest (14.5 ± 1.1 vs. 17.5 ± 1.2), tumor stage (see table), and negative surgical margins (77 vs. 87%). Patients who underwent LDP experienced lower blood loss (310 ± 68 vs. 597 ± 95 ml;
P
= 0.016*) and required fewer transfusions (0 vs. 13;
P
= 0.0008*). Patients who underwent LDP had fewer positive lymph nodes (0.8 ± 0.2 vs. 1.6 ± 0.3;
P
= 0.04*) and a lower incidence of type C pancreatic fistula (0 vs. 13%;
P
= 0.03*). Median follow-up for all patients was 11.4 months. Long-term oncologic outcomes revealed similar outcomes including distant or local recurrence (30 vs. 52%;
P
= 0.05) and median survival (18 vs. 15 months), as well as 1-year (73 vs. 59%), 3-year (22 vs. 21%), and 5-year (20 vs. 15%) survival for LDP and ODP, respectively.
Conclusions
The results of this series suggest that LDP is a safe surgical approach that is comparable from an oncologic standpoint to ODP for the management of pancreatic adenocarcinoma.
Socially assistive robots (SAR) have shown great potential to augment the social and educational development of children with autism spectrum disorders (ASD). As SAR continues to substantiate itself ...as an effective enhancement to human intervention, researchers have sought to study its longitudinal impacts in real-world environments, including the home. Computational personalization stands out as a central computational challenge as it is necessary to enable SAR systems to adapt to each child's unique and changing needs. Toward that end, we formalized personalization as a hierarchical human robot learning framework (hHRL) consisting of five controllers (disclosure, promise, instruction, feedback, and inquiry) mediated by a meta-controller that utilized reinforcement learning to personalize instruction challenge levels and robot feedback based on each user's unique learning patterns. We instantiated and evaluated the approach in a study with 17 children with ASD, aged 3-7 years old, over month-long interventions in their homes. Our findings demonstrate that the fully autonomous SAR system was able to personalize its instruction and feedback over time to each child's proficiency. As a result, every child participant showed improvements in targeted skills and long-term retention of intervention content. Moreover, all child users were engaged for a majority of the intervention, and their families reported the SAR system to be useful and adaptable. In summary, our results show that autonomous, personalized SAR interventions are both feasible and effective in providing long-term in-home developmental support for children with diverse learning needs.
Lung transplantation is the only treatment for end-stage lung disease; however, donor organ shortage and intense immunosuppression limit its broad clinical impact. Bioengineering of lungs with ...patient-derived cells could overcome these problems. We created bioartificial lungs by seeding human-derived cells onto porcine lung matrices and performed orthotopic transplantation to assess feasibility and in vivo function. Porcine decellularized lung scaffolds were seeded with human airway epithelial cells and human umbilical vein endothelial cells. Following in vitro culture, the bioartificial lungs were orthotopically transplanted into porcine recipients with planned 1-day survival (n = 3). Lungs were assessed with histology and in vivo function. Orthotopic transplantation of cadaveric lungs was performed as control. Engraftment of endothelial and epithelial cells in the grafts were histologically demonstrated. Technically successful orthotopic anastomoses of the vasculatures and airway were achieved in all animals. Perfusion and ventilation of the lung grafts were confirmed intraoperatively. The gas exchange function was evident immediately after transplantation; PO2 gradient between pulmonary artery and vein were 178 ± 153 mm Hg in the bioartificial lung group and 183 ± 117 mm Hg in the control group. At time of evaluation 24 hours after reperfusion, the pulmonary arteries were found to be occluded with thrombus in all bioartificial lungs. Engineering and orthotopic transplantation of bioartificial lungs with human cells were technically feasible in a porcine model. Early gas exchange function was evident. Further progress in optimizing recellularization and maturation of the grafts will be necessary for sustained perfusability and function.
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Cytomorphology evaluation of bone marrow cell is the initial step to diagnose different hematological diseases. This assessment is still manually performed by trained specialists, who may be a ...bottleneck within the clinical process. Deep learning algorithms are a promising approach to automate this bone marrow cell evaluation. These artificial intelligence models have focused on limited cell subtypes, mainly associated to a particular disease, and are frequently presented as black boxes. The herein introduced strategy presents an engineered feature representation, the region-attention embedding, which improves the deep learning classification performance of a cytomorphology with 21 bone marrow cell subtypes. This embedding is built upon a specific organization of cytology features within a squared matrix by distributing them after pre-segmented cell regions, i.e., cytoplasm, nucleus, and whole-cell. This novel cell image representation, aimed to preserve spatial/regional relations, is used as input of the network. Combination of region-attention embedding and deep learning networks (Xception and ResNet50) provides local relevance associated to image regions, adding up interpretable information to the prediction. Additionally, this approach is evaluated in a public database with the largest number of cell subtypes (21) by a thorough evaluation scheme with three iterations of a 3-fold cross-validation, performed in 80% of the images (n = 89,484), and a testing process in an unseen set of images composed by the remaining 20% of the images (n = 22,371). This evaluation process demonstrates the introduced strategy outperforms previously published approaches in an equivalent validation set, with a f1-score of 0.82, and presented competitive results on the unseen data partition with a f1-score of 0.56.
El objetivo de este artículo es analizar el capítulo “Men Against Fire” de Black Mirror, la serie británica emitida en Netflix, mediante el uso de dos herramientas teóricas y críticas como son la ...noción de “ficción inmunitaria” de Roberto Esposito y de “falsa conciencia” como primera definición de ideología producida dentro de la tradición marxista. Ambientada en un lugar y en un tiempo sin determinar, aunque posiblemente en un futuro no demasiado lejano, “Men Agaist Fire” trata de una comunidad que necesita inmunizarse ante la presencia de unos individuos que, estigmatizados como enfermos, pueden desestabilizar la comunidad por medio del contagio y poner en riesgo la supervivencia de la comunidad. Hay que levantar una frontera inmunitaria para salvar la especie, construir una ficción o una falsa conciencia que actúe como un muro que impida la entrada de esos individuos en la comunidad. Construir un otro que evidencie que ellos no son como nosotros. Este artículo tratará de mostrar el modo en que la construcción del otro como sujeto deshumanizado no solamente funciona como un relato construido al servicio de la protección de la comunidad, sino también como una forma de producir indiferencia y de este modo suspender las reacciones morales por parte de quien aprieta el gatillo en la guerra para aniquilar al enemigo. Frente a este discurso construido por quienes están en el poder, se plantea la necesidad de reivindicar la noción de verdad como instrumento para combatir las ficciones del poder.
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