introduction: multileaf collimator (mlc) is state of the art among the radiation field shaping systems for conformal radiotherapy techniques. some advantages of this system are as follow: reduction of treatment time, higher precision in conforming the radiation field to the projection of the target volume and lowering the chance of errors made by technologists. the purpose of this research was ...

In application of wireless sensor network, the position information of sensor node is crucial within life cycle in the whole network. In order to design algorithm of node positioning with high-efficiency, high-precision and low-consumption, this paper puts forward using the encryption algorithm of space control node originally applied in field of engineering measurement, by using SDI algorithm ...

1.1 Ultra-precision moving positioning stage A typical ultra-precision moving positioning stage is often used in ultra-precision manufacturing system for its nanometer displacement and fast linear moving speed. Usually, such platform consists of electric amplifiers, piezoelectric actuators and loads. As hysteresis is inherent in piezoelectric actuator, the amplifier and load can be considered a...

This paper presents the control performance of a highprecision positioning device using the hybrid actuator composed of a piezoelectric (PZT) actuator and a voice-coil motor (VCM). The combined piezo-VCM actuator features two main characteristics: a large operation range due to long stroke of the VCM, and high precision and heavy load positioning ability due to PZT impact force. A one-degree-of...

Many application areas such as semiconductor manufacture, precision optics alignment, and microbiological cell manipulation require ultraprecision positioning systems with a high positioning resolution and large motion range. This article describes the development of a compact high precision linear piezoelectric stepping positioner for precision alignment of optical elements. The positioner is ...

The use of GPS for indoor positioning poses difficult challenges due to very weak signal levels, and accuracies are typically of the order of tens to hundreds of metres at best. To overcome this severe limitation Locata Corporation has invented a new positioning technology called Locata, for precision positioning both indoors and outside. Part of the “Locata technology” consists of a time-synch...

The use of GPS for indoor positioning poses difficult challenges due to very weak signal levels, and accuracies are typically of the order of tens to hundreds of metres at best. To overcome this severe limitation, Locata Corporation has invented a new positioning technology called Locata, for precision positioning both indoors and outside. Part of the “Locata technology” consists of a time-sync...

In this contribution we present the results of three different studies in which the method of least-squares variance component estimation (LS-VCE) was used to infer the stochastic properties of GPS data. The three studies cover the GPS geometry-free model, the GPS coordinate time series model, and the GPS zero-baseline model. In the GPS geometry-free model, LS-VCE is applied to assess the preci...