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Applicability of a set of tomographic reconstruction algorithms for quantitative SPECT on irradiated nuclear fuel assemblies

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NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 2015年 783卷 128-141页

作者： Svard, Staffan Jacobsson Holcombe, Scott Grape, Sophie Uppsala Univ Dept Phys & Astron SE-75120 Uppsala Sweden

A fuel assembly operated in a nuclear power plant typically contains 100-300 fuel rods, depending on fuel type, which become strongly radioactive during irradiation in the reactor core. For operational and security reasons, it is of interest to experimentally deduce rod-wise information from the fuel, preferably by means of non-destructive measurements. The tomographic SPECT technique offers such possibilities through its two-step application;(1) recording the gamma-ray flux distribution around the fuel assembly, and (2) reconstructing the assembly's internal source distribution, based on the recorded radiation field. In this paper, algorithms for performing the latter step and extracting quantitative relative rod-by-rod data are accounted for. As compared to application of SPECT in nuclear medicine, nuclear fuel assemblies present a much more heterogeneous distribution of internal attenuation to gamma radiation than the human body, typically with rods containing pellets of heavy uranium dioxide surrounded by cladding of a zirconium alloy placed in water or air. This inhomogeneity severely complicates the tomographic quantification of the rod-wise relative source content, and the deduction of conclusive data requires detailed modelling of the attenuation to be introduced in the reconstructions. However, as shown in this paper, simplified models may still produce valuable information about the fuel. Here, a set of reconstruction algorithms for SPECT on nuclear fuel assemblies are described and discussed in terms of their quantitative performance for two applications;verification of fuel assemblies' completeness in nuclear safeguards, and rod wise fuel characterization. It is argued that a request not to base the former assessment on any a priori information brings constraints to which reconstruction methods that may be used in that case, whereas the use of a priori information on geometry and material content enables highly accurate quantitative assessment, which may

关键词： Tomography Nuclear fuel Reconstruction Radon transform Analytic algorithm algebraic algorithm

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Direct algorithms for solving some inverse source problems in 2D elliptic equations

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INVERSE PROBLEMS 2015年第10期31卷 105002-105002页

作者： Abdelaziz, Batoul El Badia, Abdellatif El Hajj, Ahmad Univ Technol Compiegne Univ Paris 04 LMAC F-60205 Compiegne France

This paper deals with the resolution of some inverse source problems in the 2D elliptic equation Delta u + mu u = F from Cauchy data. Two types of sources are considered, pointwise sources and sources having compact support within a finite number of small subdomains. An identification direct algorithm, based on an algebraic approach, is proposed. This is a new result, as far as we know, except in the case mu = 0 which is already considered in El Badia and Ha-Duong (2000 Inverse Problems 16 651-63).

关键词： 2D Helmholtz's equation inverse source problems algebraic algorithm

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Improved MDA, a case for de-garbling SSR mode S replies

Improved MDA, a case for de-garbling SSR mode S replies

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Tyrrhenian International Workshop on Digital Communications - Enhanced Surveillance of Aircraft and Vehicles (TIWDC/ESAV)

作者： Petrochilos, N. Piracci, E. G. Galati, G. Univ Reims CRESTIC BP 1039 F-51687 Reims 2 France Tor Vergata Univ D I E Rome Italy Tor Vergata Univ Vito Volterra Ctr Rome Italy

ISBN: (纸本)9781479930944

Multilateration (MLAT) and Automatic Dependent Surveillance - Broadcast (ADS-B) systems exploiting the Secondary Surveillance Radar (SSR) channel suffer from garbling. This means that if two or more mode S signals impinge on the receiver at the same or very near time they could not be decoded. To alleviate this problem, many solutions have been proposed, one in particular [1] is effective for a large variety of scenarios, but excluding the cases when the replies are too much separated in time. Recently a paper [2] focused on linear algebra presented a potential solution for this case. In this work we present a practical application for the case of two mode S signals.

关键词： Mode S SSR ADS-B Multilateration signals separation algebraic algorithm joint diagonalisation

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algebraic data retrieval algorithms for multi-channel wireless data broadcast

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THEORETICAL COMPUTER SCIENCE 2013年 497卷 123-130页

作者： Gao, Xiaofeng Lu, Zaixin Wu, Weili Fu, Bin Shanghai Jiao Tong Univ Dept Comp Sci Shanghai 200030 Peoples R China Univ Texas Dallas Dept Comp Sci Richardson TX 75083 USA Univ Texas Pan Amer Dept Comp Sci Edinburg TX 78541 USA

Wireless data broadcast is an important data dissemination method for distributing public information to mobile users. Due to the exponentially increasing number of mobile network users, it is necessary to develop efficient data retrieval protocols for end users to download data items effectively. In this paper, we concentrate on investigating scheduling algorithms for retrieving a set of data items from a multichannel wireless data broadcast system. As we know, the most important issues in mobile computing are energy efficiency and query response efficiency. However, in data broadcast the objectives of reducing access latency and energy cost can be contradictive to each other. Consequently, we define a new problem named Minimum Constraint Data Retrieval Problem (MCDR). We prove that MCDR is NP-hard, and then show a fixed parameter tractable algorithm which can balance two factors together. It has computational time O(2(k)(hnt)O-(1)), where n is the number of channels, k is the number of required data items, t is the maximal time slot, and h is the maximal number of channel switches. (C) 2012 Elsevier B.V. All rights reserved.

关键词： Data broadcast Data retrieval algebraic algorithm Mobile computing

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algebraic nonuniformity correction algorithm based on Multiscale optical flow

Algebraic nonuniformity correction algorithm based on Multis...

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4th International Symposium on Photoelectronic Detection and Imaging (ISPDI) - Advances in Infrared Imaging and Applications

作者： He Ming Wang Xin-sai Wu Qiang Liu Yu Xu Hua-liang Guo Dong Air Def Forces Command Acad Lab Infrared & Imaging Nav Technol Zhengzhou 450052 Peoples R China

ISBN: (纸本)9780819488343

A multi-scale optical flow motion estimation based algorithm is developed for algebraic nonuniformity correction. First, the algorithm use time domain low pass filter filtering the random image frames noise. Then, use multi-scale optical flow estimation of the next frame. With these scene estimates and record frame, we can carry out nonuniformity correction. The strength of the algorithm lies in its good noise immunity, simple calculation and ability of real time processing. The fundamental and the flow of the proposed technique are described and the performance is demonstrated with infrared camera developed.

关键词： Infrared focal plane arrays multi-scale optical algebraic algorithm Bilinear interpolation Low-pass filter in time domain

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Research in Reliability Modeling of WEDM Based on Neural Network

Research in Reliability Modeling of WEDM Based on Neural Net...

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International Conference on Measuring Technology and Mechatronics Automation

作者： Zhang Hong-bin Jia Zhi-xin Univ Sci & Technol Beijing Sch Mech Engn Beijing 100083 Peoples R China

ISBN: (纸本)9780769535838

Because of the small size of the Wire-Electronic Discharging Machine (WEDM) reliability data, the reliability model of WEDM can not be set up accurately by the traditional reliability modeling methods. Therefore, the neural network is used in this paper to solve this problem. The algebraic algorithm, a new algorithm of neural network, is used in the proposed method. Based on statistically analyzing the reliability data of WEDM, the general idea and basic method is proposed for setting up reliability model by neural network, and a new way of reliability modeling is found out for WEDM reliability modeling. After an example is calculated, it is shown that the calculation time of the proposed method is 3 times, and the mean absolute error of the proposed method is 0.0156, as well as the mean absolute error of the traditional method is 0.0703. It is proved that the model which is set up by neural network can map the actual data more accurate than the traditional model. It has a good reference to WEDM reliability researching.

关键词： reliability modeling WEDM neural networ algebraic algorithm

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algebraic algorithms for structure determination in biological chemistry

Algebraic algorithms for structure determination in biologic...

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Symposium on Mathematical Methods and Symbolic Calculation in Chemistry and Chemical Biology

作者： Emiris, IZ Fritzilas, ED Manocha, D Natl Univ Athens Dept Informat & Telecommun Athens 15784 Greece Natl Univ Athens Dept Biol Athens 15784 Greece Univ N Carolina Dept Comp Sci Chapel Hill NC 27599 USA

Several problems in computational chemistry, structural molecular biology, and biological chemistry can be solved by symbolic-numerical algorithms. We introduce suitable algebraic tools and then survey their usage in concrete applications. In particular, questions on molecular structure can be modeled by systems of polynomial equations, mainly by drawing on techniques from robot kinematics. Resultant-based algorithms, including sparse resultants and their matrix formulae, are described in order to reduce the solving of polynomial systems to numerical linear algebra. As an illustration, we focus on computing all conformations of cyclic molecules and on matching pharmacophores under distance constraints;in both cases, the number of independent degrees of freedom is relatively small. We summarize some existing results as well as sketch some original work. Both lead to complete and accurate solutions for those problems in the sense that our algorithms output all solutions with sufficiently high precision for the needs of biochemical applications. (c) 2005 Wiley Periodicals, Inc.

关键词： molecular conformation geometric constraint pharmacophore algebraic algorithm symbolic-numerical method

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algebraic algorithms for structure determination in biological chemistry

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INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY 2006年第1期106卷 190-210页

关键词： molecular conformation geometric constraint pharmacophore algebraic algorithm symbolic-numerical method

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Amplitude distortion compensation for voltage source dc/ac inverters

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INTERNATIONAL JOURNAL OF ELECTRONICS 2004年第2期91卷 83-96页

作者： Chen, YM Cheng, YM Natl Chung Cheng Univ Dept Elect Engn Power Elect Appl Res Lab Chiayi Taiwan

The objective of this paper is to propose two different modified sinusoidal pulse width modulation (SPWM) control schemes, MPWM-S and MPWM-T, for the dc/ac inverter with a non-constant dc voltage source. The amplitude distortion of the pulse width modulated waveforms is caused by the input dc voltage source variation and has the most significant impact on the dc/ac inverter's ac output voltage spectral errors. The proposed MPWM-S and MPWM-T can achieve the desired fundamental amplitude and eliminate the low order harmonic components caused by the dc voltage source variation. The mathematical analysis of the amplitude distortion and the systematic development of the MPWM-S and MPWM-T are presented in this paper. The proposed MPWM-S and MPWM-T are feed-forward compensation methodologies and can be integrated with any practical feedback control schemes. Hardware implementations of the proposed control schemes can be easily accomplished by adding one or two analog multipliers to the traditional SPWM control circuit. The performance of the two proposed modified SPWM control schemes is verified by experimental results.

关键词： PULSEWIDTH MODULATION algebraic algorithm

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An algebraic algorithm to isolate complex polynomial zeros using sturm sequences

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COMPUTERS & MATHEMATICS WITH APPLICATIONS 2000年第3-4期39卷 95-105页

作者： Brunetto, MAOC Claudio, DM Trevisan, V UEL Dept Comp BR-86051970 Londrina PR Brazil PUC RS Inst Matemat BR-90610001 Porto Alegre RS Brazil UFRGS Inst Matemat BR-91509900 Porto Alegre RS Brazil

In this paper, algorithms to enumerate and isolate complex polynomial roots are developed, analyzed,and implemented. We modified an algorithm due to Wilf, in which Sturm sequences and the principle of argument are used, by employing algebraic methods, aiming to enumerate zeros inside a rectangle in an exact way. Several improvements are introduced, such as dealing with zeros on the boundary of the rectangle. The performance of this new algorithm is evaluated in a theoretical as well as from a practical point of view, by means of experimental tests. The robustness of the algorithm is verified by using tests with ill-conditioned polynomials. We also compare the performance of this algorithm with the results of a recent paper, using different polynomial classes. (C) 2000 Elsevier Science Ltd. All rights reserved.

关键词： polynomial zeros sturm sequences algebraic algorithm

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