Background: Femoral stem anteversion during hip arthroplasty is generally estimated by eye intraoperatively and hasproven to be different from targeted values. This study aims to determine the accuracy of a novel technique using adigital protractor and a spirit level to improve surgeons’ estimation of stem anteversion.Methods: A prospective non-randomized study was conducted a...

Visual estimation of object stability is an ecologically important judgment that allows observers to predict the physical behavior of objects. A natural method that has been used in previous work to measure perceived object stability is the estimation of perceived "critical angle"--the angle at which an object appears equally likely to fall over versus return to its upright stable position. For...

Visual estimation of object stability is an ecologically important judgment that allows observers to predict the physical behavior of objects. A natural method that has been used in previous work to measure perceived object stability is the estimation of perceived “critical angle” – the angle at which an object appears equally likely to fall over versus return to its upright stable position. Fo...

A novel observer structure for vehicle side slip angle (β ) estimation is proposed, in which a local approximation of the nonlinear tire model is adopted. Fuzzy logic approach is adopted to combine the local observer models so as to deal with the nonlinear nature of vehicle dynamics. The derivation of observer’s state equations and the estimation mechanism is developed. By choosing the membersh...

The problem of position estimation in sensor networks using a combination of distance and angle information as well as pure angle information is discussed. For this purpose, a semidefinite programming relaxation based method that has been demonstrated on pure distance information is extended to solve the problem. Practical considerations such as the effect of noise and computational effort are ...