Search results for "Machine"
showing 10 items of 2592 documents
Which Is Which? Evaluation of Local Descriptors for Image Matching in Real-World Scenarios
2019
Matching with local image descriptors is a fundamental task in many computer vision applications. This paper describes the WISW contest held within the framework of the CAIP 2019 conference, aimed at benchmarking recent descriptors in challenging planar and non-planar real image matching scenarios. According to the contest results, the descriptors submitted to the competition, most of which based on deep learning, perform significantly better than the current state-of-the-art in image matching. Nonetheless, there is still room for improvement, especially in the case of non-planar scenes.
Do trained assessors generalize their knowledge to new stimuli?
2005
Previous work showed that trained assessors are better at discriminating and describing familiar chemico-sensorial stimuli than novices. In this study, we evaluated whether this superiority holds true for new stimuli. We first trained a group of subjects to characterize beer flavors over a two year period. After training was accomplished, we compared the performance of these trained assessors with the performance of novice subjects for discrimination and matching tasks. The tasks were performed using both well-learned and new beers. Trained assessors outperformed novices in the discrimination task for learned beers but not for new beers. But on the matching task, trained assessors outperfor…
Comparison of the effect of different surface treatments on the bond strength of different cements with nickel chromium metal alloy: An in vitro study
2017
Background For success of any indirect metal restoration, a strong bond between cement and the intaglio surface of metal is imperative. The aim of this study is to evaluate and compare the effect of different surface treatment on the tensile and shear bond strength of different cements with nickel–chromium alloy. Material and Methods 120 premolars were sectioned horizontally parallel to the occlusal surface to expose the dentin. Wax patterns were fabricated for individual tooth followed by casting them in nickel chromium alloy. 60 samples were tested for tensile bond strength, and the remaining 60 for shear bond strength. The samples were divided into three groups (of 20 samples each) as pe…
Damping of rotor conical whirl by asymmetric dry friction suspension
2009
Abstract A new technique for the rotor whirl damping in rotating machinery, based on the elastic suspension of the journal boxes and the use of dry friction surfaces normal to the shaft axis between their supports and the frame, is here analysed theoretically for several cases of rotor systems characterized by mass and constraint asymmetry, where gyroscopic effects are to be expected and conical whirl motions may grow up. The critical flexural speeds can be easily cut off by an adhesive state of the supports and the whirl amplitude can be minimized as well throughout the remaining sliding range. Confining the operative angular speed of the rotor in the range of adhesive contact between the …
Comparison of spring characteristics of titanium-molybdenum alloy and stainless steel
2017
Background Titanium-molybdenum alloy (TMA) and stainless steel (SS) wires are commonly used in orthodontics as arch-wires for tooth movement. However, plastic deformation phenomenon in these arch-wires seems to be a major concern among orthodontists. This study aimed to compare the mechanical properties of TMA and SS wires with different dimensions. Material and Methods Seventy-two wire samples (36 TMA and 36 SS) of three different sizes (19×25, 17×25 and 16×22) were analyzed in vitro, with 12 samples in each group. Various mechanical properties of the wires, including spring-back, bending moment and stiffness were determined using a universal testing machine. Student’s t-test showed statis…
Effect of alloy type and casting technique on the fracture strength of implant-cemented structures.
2010
Objectives: To evaluate the influence of alloy type and casting procedure on the fracture strength (FS) of metallic frameworks for implant-supported fixed prostheses. Study design: Thirty three-unit structures for lower posterior bridges were waxed-up and randomly assigned to two groups (n=15) according to alloy type and casting technique: Group 1 (C): cobalt-chromium cast in a centrifugal machine (TS1, Degussa-Hüls); Group 2 (T): titanium cast in a pressure-differential device (Cyclarc II, Morita). Each structure was cemented onto two prefabricated abutments under a constant seating pressure. After 6 months of water aging, samples were loaded in a static universal testing machine (EFH/5/FR…
Boosting the supercapacitive behavior of CoAl-layered double hydroxides via tuning the metal composition and interlayer space
2020
Layered double hydroxides (LDHs) are promising supercapacitor materials due to their wide chemical versatility, earth abundant metals and high specific capacitances. Many parameters influencing the supercapacitive performance have been studied such as the chemical composition, the synthetic approaches, and the interlayer anion. However, no systematic studies about the effect of the basal space have been carried out. Here, two-dimensional (2D) CoAl-LDHs were synthesized through anion exchange reactions using surfactant molecules in order to increase the interlayer space (ranging from 7.5 to 32.0 Å). These compounds exhibit similar size and dimensions but different basal space to explore excl…
Boosting the Performance of One-Step Solution-Processed Perovskite Solar Cells Using a Natural Monoterpene Alcohol as a Green Solvent Additive
2021
The perovskite film is the core of a perovskite solar cell (PSC), and its quality is crucial for the performance of such devices. The morphology, crystallinity, and surface coverage of the perovskite layer greatly affect the power conversion efficiency (PCE), hysteresis, and long-term stability of PSCs. The incorporation of appropriate solvent additives in the perovskite precursor solution is an effective strategy to control the film morphology and reduce the defects and grain boundaries. However, the commonly used solvent additives are environmentally harmful and highly toxic. In this work, α-terpineol (a nontoxic, eco-friendly, and low-cost monoterpene alcohol) is employed for the first t…
Effect of water contamination on the shear bond strength of five orthodontic adhesives
2010
Objectives: To evaluate the shear bond strength and site of failure of brackets bonded to dry and wet enamel. Study design: 50 teeth were divided into ten groups of 5 teeth each (10 surfaces). In half the groups enamel was kept dry before bonding, and in the other half distilled water was applied to wet the surface after etching. The following groups were established: 1)Acid/Transbond-XT (dry/wet) XT; 2) Transbond Plus Self Etching Primer (TSEP)/Transbond-XT paste (dry/wet); 3) Concise (dry), Transbond MIP/Concise (wet), 4) FujiOrtho-LC (dry/ wet); 5) SmartBond (dry/wet). Brackets were bonded to both buccal and lingual surfaces. Specimens were stored in distilled water (24 hours at 37ºC) an…
Casein phosphopeptide-amorphous calcium phosphate effects on brackets shear bond strength and enamel damage
2017
Background The aim of study was to evaluate the application of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and fluoride regarding their effect on the shear bond strength (SBS), bond failure pattern of brackets using the adhesive remnant index (ARI) and assessing the quality of enamel surface using the enamel damage index (EDI). Material and methods Sixty extracted premolar teeth were randomly divided into four groups regarding pretreatment application of CPP-ACP and fluoride. Brackets were bonded using the conventional method. Specimens were thermocycled for 1000 cycles and were subsequently tested for the SBS in a universal testing machine. After debonding, the teeth were e…