Confidence in prediction: an approach for dynamic weighted ensemble.

Combining classifiers in an ensemble is beneficial in achieving better prediction than using a single classifier. Furthermore, each classifier can be associated with a weight in the aggregation to boost the performance of the ensemble system. In this work, we propose a novel dynamic weighted ensemble method. Based on the observation that each classifier provides a different level of confidence in its prediction, we propose to encode the level of confidence of a classifier by associating with each classifier a credibility threshold, computed from the entire training set by minimizing the entropy loss function with the mini-batch gradient descent method. On each test sample, we measure the confidence of each classifier’s output and then compare it to the credibility threshold to determine whether a classifier should be attended in the aggregation. If the condition is satisfied, the confidence level and credibility threshold are used to compute the weight of contribution of the classifier in the aggregation. By this way, we are not only considering the presence but also the contribution of each classifier based on the confidence in its prediction on each test sample. The experiments conducted on a number of datasets show that the proposed method is better than some benchmark algorithms including a non-weighted ensemble method, two dynamic ensemble selection methods, and two Boosting methods

Root canal morphology of primary maxillary second molars:a micro-computed tomography analysis

Aim Successful endodontic treatment of primary teeth requires comprehensive knowledge and understanding of root canal morphology. The purpose of this study was to investigate the root canal configurations of primary maxillary second molars using micro-computed tomography. Methods Extracted human primary maxillary second molars (n = 57) were scanned using micro-computed tomography and reconstructed to produce three-dimensional models. Each root canal system was analysed qualitatively according to Vertucci's classification. Results 22.8% (n = 13) of the sample presented with the fusion of the disto-buccal and palatal roots; of these, Type V was the most prevalent classification. For teeth with three separate roots (n = 44), the most common root canal type was Type 1 for the palatal canal (100%) and disto-buccal canal (77.3%) and Type V for the mesio-buccal canal (36.4%). Overall, 7% (n = 4) of mesio-buccal canals were 'unclassifiable'. Conclusion The root canal systems of primary maxillary second molars were not only complex but had a range of configurations that may contribute to unfavourable clinical outcomes after endodontic treatment

Automated Ham Quality Classification Using Ensemble Unsupervised Mapping Models

This multidisciplinary study focuses on the application and comparison of several topology preserving mapping models upgraded with some classifier ensemble and boosting techniques in order to improve those visualization capabilities. The aim is to test their suitability for classification purposes in the field of food industry and more in particular in the case of dry cured ham. The data is obtained from an electronic device able to emulate a sensory olfative taste of ham samples. Then the data is classified using the previously mentioned techniques in order to detect which batches have an anomalous smelt (acidity, rancidity and different type of taints) in an automated way

Binarized Support Vector Machines

The widely used support vector machine (SVM) method has shown to yield very good results in supervised classification problems. Other methods such as classification trees have become more popular among practitioners than SVM thanks to their interpretability, which is an important issue in data mining. In this work, we propose an SVM-based method that automatically detects the most important predictor variables and the role they play in the classifier. In particular, the proposed method is able to detect those values and intervals that are critical for the classification. The method involves the optimization of a linear programming problem in the spirit of the Lasso method with a large number of decision variables. The numerical experience reported shows that a rather direct use of the standard column generation strategy leads to a classification method that, in terms of classification ability, is competitive against the standard linear SVM and classification trees. Moreover, the proposed method is robust; i.e., it is stable in the presence of outliers and invariant to change of scale or measurement units of the predictor variables. When the complexity of the classifier is an important issue, a wrapper feature selection method is applied, yielding simpler but still competitive classifiers

Evaluation of root canal morphology of human primary mandibular second molars by using cone beam computed tomography

Objectives: The aim of the present study was to investigate the root canal configurations of primary mandibular second molars (PMSMs) using Vertucci classification. Materials and Methods: The root canal types of 228 PMSMs (228 mesial and 228 distal roots) were evaluated. In addition, the relationship between external root morphology and Vertucci classification was investigated. The Chi‑square test or Fisher Exact Chi‑square test was used for the evaluations, and P < 0.05 was considered statistically significant for all tests. Results: The most commonly observed root canal type, which was observed in 228 roots (50%), was Type 4 followed by Type 8 (15.79%), Type 5 (14.47%), Type 1 (9.21%), and Type 3 (6.57%). In 150 mesial roots, the root canal Type 4 was observed whereas the same type was observed in 78 distal roots, and the difference was significant (P < 0.001). In flat roots (82.9%), the most frequently observed root canal type was Type 4 (50.8%) (P < 0.001).Conclusion: Various root canal types were observed in both mesial and distal roots although Type 4 was the most commonly observed. Root canal types showed a  consistent relationship with separated and conical root shapes whereas the flat roots showed different root canal types.Keywords: Primary teeth, root canal, Vertucci classificatio

Retrospective evaluation of healing of periapical lesions after unintentional extrusion of mineral trioxide aggregate

Background: During the apexification procedure for teeth with open apices, mineral trioxide aggregate (MTA) may be unintentionally extruded. The aim of the present study was the retrospective evaluation of the healing of periapical lesions in permanent incisor teeth with open apices after the unintentional extrusion of MTA. Methods: The clinical and radiographic records of 55 maxillary permanent central teeth treated by MTA apexification were evaluated. Filled teeth with unintentionally extruded MTA were selected as group 1 (n = 21), whereas the teeth with no MTA extrusion were selected as group 2 (n = 34). For each tooth, the clinical and radiographic records from a 3-year follow-up were investigated. Results: Complete healing (CH) was observed in 19 teeth (90.4%) in group 1, whereas the same type of healing was observed in all 34 teeth (100%) in group 2 (p>0.05). At the 6-month follow-up appointment, 25 teeth (73.5%) showed CH in group 2, whereas 15 teeth (71.4%) showed CH at the 1-year follow-up in group 1 (p<0.001). At the end of the 3-year follow-up period, the amount of MTA extrusion was reduced in 17 teeth (85%) (p<0.05), whereas it was almost absent in 2 teeth (10%). conclusions: The unintentional extrusion of MTA does not prevent the healing of periapical lesions, but may be a delaying factor for periapical healing. © 2017 The Authors

Severe unintentional extrusion of mineral trioxide aggregate during apexification

The aim of this report was to present the long-term clinical and radiographic outcomes of a case including severe unintentional extrusion of mineral trioxide aggregate (MTA). An 11-year-old boy was referred with a previously traumatized permanent central incisor which was temporarily treated by using calcium hydroxide root canal filling material. Since having an open apex and a large periapical lesion, root canal treatment with MTA apexification was planned. During the apexification process, a huge amount of MTA was unintentionally extruded into periapical tissues. The parents were informed about the complication, and the obturation of the remaining root canal was completed. Clinical and radiographic follow-up was performed for 4 years. Complete healing of periapical lesion was confirmed by the radiographic follow-up at the 48th month. Patients should be followed-up for giving a chance to observe periapical healing without any surgical removal if the MTA is unintentionally extruded. © 2017 Indian Journal of Dental Research