This paper is concerned with the frictionless unilateral contact problem (i.e., a Signorini problem with the elasticity operator). We consider a mixed finite element method in which the unknowns are the displacement field and the contact pressure. The particularity of the method is that it furnishes a normal displacement field and a contact pressure satisfying the sign conditions of the continu...

volume estimation of most agricultural products using mathematical methods is not accurate because of their irregular shape. an alternative method is image processing, which can be used in continuous sorting machines. the objective of this study is to find a practical method for volume estimation of potatoes using image processing. fifty potatoes (marfona variety) were selected as experimental ...

To achieve the accurate measurement of the hydraulic valve opening position, the sensor measurement circuit was designed for two and three differential solenoid coil inductance displacement sensor. Some experiments were done to detect the static and dynamic performance. Comparing the static output characteristic of the two type of the sensor. The experimental results of the actual measurement o...

Registration error resulting from intraoperative brain shift due to applied surgical loads has long been recognized as one of the most challenging problems in the field of frameless stereotactic neurosurgery. To address this problem, we have developed a 3-dimensional finite element model of the brain and have begun to quantify its predictive capability in an in vivo porcine model. Previous stud...

There are mainly two types of errors existed in monitoring displacement of a rock slope: gross errors and random errors. Monitoring data is very important for the safety construction and operation of the Hydropower Station. The use of slope monitoring data for safety evaluation is influenced by the gross errors during the monitoring process. This paper presents a gross error denosing method for...

Larynx may alternatively serve as a target or organs at risk (OAR) in head and neck cancer (HNC) image-guided radiotherapy (IGRT). The objective of this study was to estimate IGRT parameters required for larynx positional error independent of isocentric alignment and suggest population-based compensatory margins. Ten HNC patients receiving radiotherapy (RT) with daily CT on-rails imaging were a...

The symmetric coupling of mixed nite element and boundary element methods is analysed for a model interface problem with the Laplacian. The coupling involves a further continuous ansatz function on the interface to link the discontinuous displacement eld to the necessarily continuous boundary ansatz function. Quasi-optimal a priori error estimates and sharp a posteriori error estimates are esta...

The goal of this study was to identify and model the three-dimensional (3-D) geometric transformations required for accurate saccades to distant visual targets from arbitrary initial eye positions. In abstract 2-D models, target displacement in space, retinal error (RE), and saccade vectors are trivially interchangeable. However, in real 3-D space, RE is a nontrivial function of objective targe...

A small scale, high precision co-ordinate table was developed as part of a project to solve measurement problems originating from microtechnic. Construction with a single reference surface was selected and vacuum preloaded air bearing applied in order to enable smooth motion and eliminate stick slip. Laser interferometers were applied to measure both the displacement and the angular error. The ...

In this paper goal-oriented error control based on dual weighted residual error estimations (DWR) is applied to frictional contact problems. A mixed formulation of the contact problem is used to derive a discretization. It relies on the introduction of Lagrange multipliers to capture the frictional contact conditions. The discretization error is estimated in terms of functionals (the quantities...