We describe a method for transforming beam search into a complete search algorithm that is guaranteed to find an optimal solution. Called beam-stack search, the algorithm uses a new data structure, called a beam stack, that makes it possible to integrate systematic backtracking with beam search. The resulting search algorithm is an anytime algorithm that finds a good, sub-optimal solution quick...

We designed and implemented a linear programming based IMRT treatment plan generation technology that effectively and efficiently optimizes beam geometry as well as beam intensities. The core of the technology is a fluence map optimization model that approximates partial dose volume constraints using conditional value-at-risk constraints. Conditional value-at-risk constraints require careful tu...

The emerging space-air-ground integrated network has attracted intensive research and necessitates reliable efficient aeronautical communications. This paper investigates terahertz Ultra-Massive (UM)-MIMO-based communications proposes an effective channel estimation tracking scheme, which can solve the performance degradation problem caused by unique <italic xmlns:mml="http://www.w3.org/1998/Ma...

In application of tomography imaging, limited-angle problem is a quite practical and important issue. In this paper, an iterative reprojection-reconstruction (IRR) algorithm using a modified Papoulis-Gerchberg (PG) iterative scheme is developed for reconstruction from limited-angle projections which contain noise. The proposed algorithm has two iterative update processes, one is the extrapolati...

Iterative PET image reconstructions can improve quantitation accuracy by explicitly modeling photon-limited nature and physical effects of coincident photons. Geometric model in iterative reconstructions defines the mapping between image and sinogram domains based on scanners geometry, which affects the accuracy of image results and the convergence rate of reconstruction algorithms. This paper ...

Wide-swath SAR imagery obtained by the RADARSAT ScanSAR mode can suffer from radiometric artifacts. These artifacts arise from improper application of Range Dependent Gain Corrections (RDGCs), mainly due to insufficient knowledge of the satellite’s roll angle. Specifically, roll angle estimation errors as small as 0.1 degrees can cause noticeable gain errors of 1 dB or more. Beam-stitching tech...

We present computational approaches for optimizing beam angles and fluence maps in Intensity Modulated Radiation Therapy (IMRT) planning. We assume that the number of angles to be used for the treatment is given by the treatment planner. A mixed integer programming (MIP) model and a linear programming (LP) model are used to find an optimal set of beam angles and their corresponding fluence maps...

A fast and efficient three-dimensional generalized rectangular wide-angle beam propagation method (GR-WABPM) based on a recently proposed modified Padé (1,1) approximant is presented. In our method, at each propagation step, the beam propagation equation is recast in terms of a Helmholtz equation with a source term, which is solved quickly and accurately by a recently introduced complex Jacobi ...

the pseudo-elastic behavior of shape memory alloy (sma) truss and cantilever beam are investigated. brinson’s one-dimensional material model, which uses the twinned and detwinned martensite fractions separately as internal variables, is applied in the algorithm to establish the sma stress-strain characteristics. this material model also incorporates different young’s modulus for austenitic and ...