background and aims. at present, cone beam computed tomography (cbct) has become a substitute for computed tomography (ct) in dental procedures. the metallic materials used in dentistry can produce artifacts due to the beam hardening phenomenon. these artifacts decrease the quality of images. in the present study, the number of artifacts as a result of beam hardening in the images of dental imp...

We investigate the issue of global energy efficiency optimization in a multi-beam low Earth orbit (LEO) satellite communication system. Current terrestrial networks provide high-quality and cost mainly densely populated areas. However, extending wideband coverage to remote areas is unaffordable. LEO satellites solution for offering by supporting networks. consider downlink transmissions Ka-band...

PURPOSE Craniospinal irradiation poses technical difficulties that may be addressed with the use of the newer technologies that have become available over the past decade. The use of CT simulation allows improved target localisation and beam geometry definition while significantly reducing the treatment simulation time. We have developed a CT-based technique for whole CNS irradiation in the sup...

A unified evolutionary approach to coplanar radiotherapy inverse planning is proposed. It consists of a genetic algorithm-based framework that solves with little modification treatment planning for three different kinds of radiation therapy: conformal, aperture-based and intensity modulated. Thanks to evolutionary optimisation techniques we have been able to search for full beam configurations,...

For interstellar missions, directed energy is envisioned to drive wafer-scale spacecraft to relativistic speeds. Spacecraft propulsion is provided by a large array of phase-locked lasers, either in Earth orbit or stationed on the ground. The directed-energy beam is focused on the spacecraft, which includes a reflective sail that propels the craft by reflecting the beam. Fluctuations and asymmet...

This paper deals with the design of a periodic output feedback controller for a flexible beam structure modeled with Timoshenko beam theory, Finite Element Method, State space methods and embedded piezoelectrics concept. The first 3 modes are considered in modeling the beam. The main objective of this work is to control the vibrations of the beam when subjected to an external force. Shear piezo...

A unified evolutionary approach to coplanar radiotherapy inverse planning is proposed. It consists of a genetic algorithm-based framework that solves with little modification treatment planning for three different kinds of radiation therapy: conformal, socalled aperture-based and intensity modulated. Thanks to evolutionary optimisation techniques we have been able to search for full beam config...

This paper features the modelling and design of a type of multirate output feedback based controller (Fast Output Sampling Feedback FOS) to control the flexural vibrations of a smart flexible Timoshenko cantilever beam for a Single Input Single Output (SISO) case by retaining the first 2 dominant vibratory modes. Piezoelectric patches are bonded as sensor / actuator to the master structure at d...