One of the most widely studied problems of the intensity-modulated radiation therapy (IMRT) treatment planning problem is the fluence map optimization (FMO) problem, the problem of determining the amount of radiation intensity, or fluence, of each beamlet in each beam. For a given set of beams, the fluences of the beamlets can drastically affect the quality of the treatment plan, and thus it is critical to obtain good fluence maps for radiation delivery. Although several approaches have been shown to yield good solutions to the FMO problem, these solutions are not guaranteed to be optimal. This shortcoming can be attributed to either optimization model complexity or properties of the algorithms used to solve the optimization model. We present a convex FMO formulation and an interior point algorithm that yields an optimal treatment plan in seconds, making it a viable option for clinical applications.
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http://dx.doi.org/10.1088/0031-9155/55/18/013 | DOI Listing |
Front Sociol
January 2025
Faculty of Social and Human Sciences, University of Beira Interior, Covilhã, Portugal.
The platform economy has contributed to new ways of organising business, work, and consumption. To understand the shape and scope of these changes, it is crucial to pay simultaneous attention to these three domains. The new ways of organising, dividing and coordinating work are interlinked with specific ways of consuming services made available by digital platforms.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Institute of Photoelectronic Thin Film Devices and Technology, Tianjin Key Laboratory of Thin Film Devices and Technology, Nankai University, Tianjin 300350, China.
Kesterite Cu2ZnSn(S,Se)4 (CZTSSe) has emerged as a promising photovoltaic material due to its low cost and high stability. The CZTSSe film for high-performance solar cells can be obtained by annealing the deposited CZTS precursor films with selenium (a process known as selenization). The design of the selenization process significantly affects the quality of the absorber layer.
View Article and Find Full Text PDFPhotoacoustics
February 2025
College of Engineering, Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
A novel balloon-type photoacoustic cell (BTPAC) is proposed to facilitate the detection limitations of acetylene (CH) gas achieving ppb level. Here, an ellipsoidal photoacoustic cavity is employed as the platform for gas-light interaction. By strategically directing the excitation source towards the focal point of the ellipsoidal cavity, ensuring its trajectory traverses the focal point upon each reflection from the interior walls.
View Article and Find Full Text PDFMol Biol Cell
January 2025
Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, the Netherlands.
The cellular interior is a spatially complex environment shaped by non-trivial stochastic and biophysical processes. Within this complexity, spatial organizational principles-also called spatial phenotypes-often emerge with functional implications. However, identifying and quantifying these phenotypes in the stochastic intracellular environment is challenging.
View Article and Find Full Text PDFMath Ann
July 2024
Department of Mathematics, Virginia Tech, Blacksburg, VA 24061 USA.
In this paper we show that if a compact set , , has Hausdorff dimension greater than when or when , then the set of congruence class of simplices with vertices in has nonempty interior. By set of congruence class of simplices with vertices in we mean where . This result improves the previous best results in the sense that we now can obtain a Hausdorff dimension threshold which allow us to guarantee that the set of congruence class of triangles formed by triples of points of has nonempty interior when as well as extending to all simplices.
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