Search results for "Poster"

On Optimizing Locally Linear Nearest Neighbour Reconstructions Using Prototype Reduction Schemes

2010

This paper concerns the use of Prototype Reduction Schemes (PRS) to optimize the computations involved in typical k-Nearest Neighbor (k-NN) rules. These rules have been successfully used for decades in statistical Pattern Recognition (PR) applications, and have numerous applications because of their known error bounds. For a given data point of unknown identity, the k-NN possesses the phenomenon that it combines the information about the samples from a priori target classes (values) of selected neighbors to, for example, predict the target class of the tested sample. Recently, an implementation of the k-NN, named as the Locally Linear Reconstruction (LLR) [11], has been proposed. The salien…

A comparison of different optimization algorithms for retrieving aerosol optical depths from satellite data: an example of using a dual-angle algorit…

2011

Optimization techniques are often used in remote sensing retrieval of surface or atmospheric parameters. Nevertheless, different algorithms may exhibit different performances for the same optimization problem. Comparison of some classic optimization approaches in this article aims to select the best method for retrieving aerosol opacity, or even for other parameters, from remotely sensed data. Eight frequently used optimization algorithms were evaluated using both simulated data and actual AATSR advanced along track scanning radiometer data. Several typical land cover types and aerosol opacity levels were also considered in the simulations to make the tests more representative. It was obser…

Guaranteed lower bounds for cost functionals of time-periodic parabolic optimization problems

2019

In this paper, a new technique is shown for deriving computable, guaranteed lower bounds of functional type (minorants) for two different cost functionals subject to a parabolic time-periodic boundary value problem. Together with previous results on upper bounds (majorants) for one of the cost functionals, both minorants and majorants lead to two-sided estimates of functional type for the optimal control problem. Both upper and lower bounds are derived for the second new cost functional subject to the same parabolic PDE-constraints, but where the target is a desired gradient. The time-periodic optimal control problems are discretized by the multiharmonic finite element method leading to lar…

Association between sella turcica bridging and altered direction of dental eruption: A case-control study

2019

Background Calcification between the anterior and posterior clinoid processes, also the so-called sella turcica bridging, has been associated in some studies with skeletal anomalies as well as with dental and eruption disturbances. It was hypothesized that sella turcica bridging was associated with an altered direction of dental eruption. The aim of the study was to assess whether there was a relationship between the degree of calcification and the presence or absence of an alteration in the tooth eruption direction. Material and methods A case-control multicenter study was conducted. The study population consisted of 150 subjects (age 10-50 years), 30 of which presented some type of altera…

Mechanical properties of the NiTi Memoria Leaf Spring Activated Expander (NiTi MLSAE) for maxillary transverse discrepancy correction: An in-vitro st…

2020

Background To determine the mechanical properties of the NiTi Memoria® Leaf Spring Activated Expander (NiTi MLSAE) in two forms, unaltered (unbent) and altered (bent) to mimic clinical use. Material and Methods This in-vitro pilot study was conducted using eight NiTi MLSAE expanders (American Tooth Industries, Oxnard, California) representing four force magnitudes: 10mm 500g, 10mm 900g, 6mm 450g and 6mm 900g models. Two experiments were performed: the first tested the expanders in their unbent form and the second tested them after they were bent by one experienced technician. All expanders were adapted to a standard three dimensional printed maxillary study model. A Dillion Quantrol 500N (1…

Biomechanical Study of the Osteoporotic Spine Fracture: Optical Approach

2021

Background and objectives: Osteoporotic spine fractures represent a significant factor for decreasing quality of life in the elderly female population. Understanding the mechanisms involved in producing these fractures can improve their prevention and treatment. This study presents a biomechanical method to produce a vertebral fracture, conducted on a human spine segment, observing the displacements and strains in the intervertebral disc, endplate, and vertebral body. Materials and Methods: We performed two tests, one corresponding to an extension loading, and the second to an axial loading. Results: The maximum displacement in the target vertebral body presented higher values in the case o…

Sagittal, rotational and transverse changes with three intraoral distalization force systems : Jones jig, distal jet and first class

2020

Background To compare the maxillary dentoalveolar changes of patients treated with three distalization force systems: Jones Jig, Distal Jet and First Class appliances, using digitized models. Material and Methods The retrospective sample comprised 118 digitized models of 59 patients with Class II malocclusion divided into three groups: Group 1 consisted of 22 patients treated with the Jones Jig appliance; Group 2 consisted of 20 patients treated with the Distal Jet, and Group 3 comprised 17 patients treated with the First Class appliance. Pretreatment and post-distalization plaster models of all patients were digitized and evaluated with OrthoAnalyzerTM software. The pretreatment and post-d…

Musculoskeletal Imaging: Knee and Shoulder

2007

Comparative evaluation of the effect of impression materials and trays on the accuracy of angulated implants impressions

2018

Background Vinyl Polyether Siloxane is a newly introduced impression material and studies on that is scarce. Implant insertion in posterior mandible might be angulated due to anatomical considerations. The purpose of this study was to compare the dimensional and angular accuracy of impressions using full-arch versus sectional tray and Vinyl Polysiloxane versus Vinyl Polyether Siloxane in angulated implants. Material and Methods Four implants were placed in dental areas #19, #21, #28 and #30 of a Kennedy class I mandibular acrylic model with 30° lingual angulation. Twenty sectional and 20 full-arch open trays were made on the primary cast. Impressions were taken using Vinyl Polysiloxane and …

Extra short 4mm implants used to rehabilitation of atrophic posterior mandible. A serial case reports

2020

Rehabilitation of patients through implants in areas with severe bone resorption in the posterior mandible is a challenge in implant dentistry. In this context, extra short implants configure a treatment option for this type of patient, as they can avoid increased financial cost, treatment time and patient morbidity. The present study evaluated the marginal bone stability in individualized extra-short implants for masticatory function in the posterior mandible. Using digitized periapical radiographs of 13 extra-short implants performed on 7 patients. The mesial and distal regions of each implant were selected, from the bone crest to the region parallel to the apex, and the bone stability of…