نتایج جستجو برای: improved ray optimization

تعداد نتایج: 1030322  

This paper presents a robust hybrid improved dolphin echolocation and ant colony optimization algorithm (IDEACO) for optimization of truss structures with discrete sizing variables. The dolphin echolocation (DE) is inspired by the navigation and hunting behavior of dolphins. An improved version of dolphin echolocation (IDE), as the main engine, is proposed and uses the positive attributes of an...

E. Valian S. Mohanna S. Tavakoli,

The cuckoo search algorithm is a recently developedmeta-heuristic optimization algorithm, which is suitable forsolving optimization problems. To enhance the accuracy andconvergence rate of this algorithm, an improved cuckoo searchalgorithm is proposed in this paper. Normally, the parametersof the cuckoo search are kept constant. This may lead todecreasing the efficiency of the algorithm. To cop...

2015
Emeline Pouyet Barbara Fayard Murielle Salomé Yoko Taniguchi Francesco Sette Marine Cotte

Synchrotron Radiation (SR) based techniques such as SR-μ Fourier Transform InfraRed (FTIR) spectroscopy, SR-μ X-Ray Fluorescence (XRF), SR-μ X-Ray Absorption Near Edge Spectroscopy (XANES) and SR-μ X-Ray Diffraction (XRD) are increasingly used for the study of cultural heritage materials, as they offer enhanced spatial resolution and chemical sensitivity. For such analyses, painting fragments a...

Journal: :iranian journal of mechanical engineering transactions of the isme 0

this paper presents a clear monograph on the optimization of thermal instability resistance of the fg (functionally graded) flat structures. for this aim, two fg flat structures, namely an fg beam and an fg circular plate, are considered. these structures are assumed to obey the first-order shear deformation theory, three-parameters power-law distribution of the constituents, and clamped bounda...

Journal: :AIP conference proceedings 2016
Rachel Mak Stefan M Wild Chris Jacobsen

In x-ray spectromicroscopy, a set of images can be acquired across an absorption edge to reveal chemical speciation. We previously described the use of non-negative matrix approximation methods for improved classification and analysis of these types of data. We present here an approach to find appropriate values of regularization parameters for this optimization approach.

2012
Jiapu Zhang Yating Hou Yiju Wang Changyu Wang Xiangsun Zhang

Experimental X-ray crystallography, NMR (Nuclear Magnetic Resonance) spectroscopy, dual polarization interferometry, etc are indeed very powerful tools to determine the 3-Dimensional structure of a protein (including the membrane protein); theoretical mathematical and physical computational approaches can also allow us to obtain a description of the protein 3D structure at a submicroscopic leve...

Journal: :Comput. Graph. Forum 2015
Yan Gu Yong He Guy E. Blelloch

In this paper we propose a simple but effective method to modify a BVH based on ray distribution for improved ray tracing performance. Our method starts with an initial BVH generated by any state-of-the-art offline algorithm. Then by traversing a small set of sample rays we collect statistics at each node of the BVH. Finally, a simple but ultra-fast BVH contraction algorithm modifies the initia...

Journal: :iranian journal of medical physics 0
hossein arabi m.sc. student, radiation medicine dept., shahid beheshti university, tehran, iran. alireza kamali asl assistant professor, nuclear engineering dept., shahid beheshti university, tehran, iran. seyed mahmood reza aghamiri associate professor, nuclear engineering dept., shahid beheshti university, tehran, iran.

introduction: variable resolution x-ray (vrx) ct is a new type of ct that can image objects at various spatial resolutions. in a vrx ct scanner, the spatial resolution increases at the cost of reduction in the field of view (fov). an important factor that limits the spatial resolution of the vrx ct is the effect of focal spot size. also, the optimum magnification is different at each incident a...

2012
Andrej Vilhar Andrej Hrovat Igor Ozimek Tomaž Javornik

role in planning of modern broadband mobile radio networks. While the less accurate statistical models predict only the path loss, the more precise ray tracing techniques enable computation of additional parameters, e.g. the mean delay and the delay spread, which are significant for the 4G network planning. The existing ray tracing methods are mainly applied in the indoor and narrow urban envir...

2015
Peter Fischer Thomas Pohl Andreas K. Maier Joachim Hornegger

Motion estimation in X-ray images is a challenging task due to transparently overlapping structures from different depths. We propose to separate an X-ray sequence into a static and a dynamic layer to facilitate motion estimation. The method exploits the idea to use the minimum intensity over time and a spatial smoothness prior for both layers. For numerical optimization, we propose a condition...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید