Search results for "Calculation algorithm"
showing 4 items of 4 documents
Researching a Capacity Model for Multilane Roundabouts with Negotiation of the Right-of-Way between Antagonist Traffic Flows
2012
This article summarizes a research program designed to assess operating conditions through capacity estimation at not-conventional roundabouts characterized by a central island with a large diameter and by two (or more) entering and circulating lanes. Although giving priority to vehicles on circulatory roadway is the nominal operating rule, on-field observations highlighted that in some infrastructural schemes of the type considered in this research drivers negotiate the right-of-way according to a consensus pattern that alternates between antagonist traffic flows, similarly to that observed at all-way-stop-controlled intersections. Considering the peculiarity of the way of working at round…
A simple analytical method for heterogeneity corrections in low dose rate prostate brachytherapy
2015
In low energy brachytherapy, the presence of tissue heterogeneities contributes significantly to the discrepancies observed between treatment plan and delivered dose. In this work, we present a simplified analytical dose calculation algorithm for heterogeneous tissue. We compare it with Monte Carlo computations and assess its suitability for integration in clinical treatment planning systems. The algorithm, named as RayStretch, is based on the classic equivalent path length method and TG-43 reference data. Analytical and Monte Carlo dose calculations using Penelope2008 are compared for a benchmark case: a prostate patient with calcifications. The results show a remarkable agreement between …
Algorithms for the calculation of the view factors between human body and rectangular surfaces in parallelepiped environments
1992
Abstract The thermal comfort conditions for people in moderate thermal environments are subjected to spatial changes, depending on the radiative exchanges of the human body with the surrounding surfaces. Radiative thermal exchanges are notably accounted for by means of the “view factors” between a person in a given posture and the surface of the enclosure. These important parameters can be evaluated by means of a large set of graphs by Fanger, for rectangular surfaces. But the handling of graphs could lead to reading errors. In this paper a simple algorithm is presented, which is able to compute the required view factors. A validation, by means of a comparison against experimental data, is …
Verification of a commercial implementation of the Macro-Monte-Carlo electron dose calculation algorithm using the virtual accelerator approach.
2009
Abstract In this work, the accuracy of the implementation of the Macro Monte Carlo electron dose calculation algorithm into the radiation therapy treatment planning system Eclipse is evaluated. This implementation – called eMC – uses a particle source based on the Rotterdam Initial Phase-Space model. A three-dimensional comparison of eMC calculated dose to dose distributions resulting from full treatment head simulations with the Monte Carlo code package EGSnrc is performed using the ‘virtual accelerator’ approach. Calculated dose distributions are compared for a homogeneous tissue equivalent phantom and a water phantom with air and bone inhomogeneities. The performance of the eMC algorithm…