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Human Immunodeficiency Virus (HIV) infection model based on triangular neutrosophic cubic hesitant fuzzy number
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作者 Fazli Amin Aliya Falling 《生物数学学报:英文版》 2019年第5期137-169,共33页
In this paper,we define the basic concept of triangular neutrosophic cubic hesitant fuzzy number and their properties.We develop a triangular neutrosophic cubic hesitant fuzzy ordered weighted arithmetic averaging (TN... In this paper,we define the basic concept of triangular neutrosophic cubic hesitant fuzzy number and their properties.We develop a triangular neutrosophic cubic hesitant fuzzy ordered weighted arithmetic averaging (TNCIIFOWAA) operator and a triangular neu-trosophic cubic hesitant fuzzy ordered weighted geometric averaging (TNCIIFOWGA) operator to aggregate triangular neutrosophic cubic hesitant fuzzy number (TNCHFN) information and investigate their properties.Furthermore,a multiple attribute decision-making method based on the TNCHFOWAA operator and triangular neutrosophic cubic hesitant fuzzy ordered weighted geometric (TNCHFOWG) operator and the score function of TNCHFN is established under a TNCHFN environment.Finally,an illustrative example of investment alternatives is given to demonstrate the application and effec-tiveness of the developed approach. 展开更多
关键词 TRIANGULAR neutrosophic CUBIC hesitant FUZZY number score function TRIANGULAR neutrosophic CUBIC hesitant FUZZY ORDERED WEIGHTED arithmetic AVERAGING (TNCH-FOWAA) operator TRIANGULAR neutrosophic CUBIC hesitant FUZZY ORDERED WEIGHTED geometric AVERAGING (TNCHFOWGA) operator multiple attribute decision-making numerical application 1 and 2
A general framework for frequentist model averaging In Celebration of Professor Lincheng Zhao’s 75th Birthday
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作者 Priyam Mitra Heng Lian +2 位作者 Ritwik Mitra Hua Liang Min-ge Xie 《中国科学:数学英文版》 SCIE CSCD 2019年第2期205-226,共22页
Model selection strategies have been routinely employed to determine a model for data analysis in statistics, and further study and inference then often proceed as though the selected model were the true model that we... Model selection strategies have been routinely employed to determine a model for data analysis in statistics, and further study and inference then often proceed as though the selected model were the true model that were known a priori. Model averaging approaches, on the other hand, try to combine estimators for a set of candidate models. Specifically, instead of deciding which model is the ’right’ one, a model averaging approach suggests to fit a set of candidate models and average over the estimators using data adaptive weights.In this paper we establish a general frequentist model averaging framework that does not set any restrictions on the set of candidate models. It broaden, the scope of the existing methodologies under the frequentist model averaging development. Assuming the data is from an unknown model, we derive the model averaging estimator and study its limiting distributions and related predictions while taking possible modeling biases into account.We propose a set of optimal weights to combine the individual estimators so that the expected mean squared error of the average estimator is minimized. Simulation studies are conducted to compare the performance of the estimator with that of the existing methods. The results show the benefits of the proposed approach over traditional model selection approaches as well as existing model averaging methods. 展开更多
关键词 ASYMPTOTIC distribution BIAS variance trade-off local mis-specification model AVERAGING ESTIMATORS optimal weight selection
Homoclinic, heteroclinic and periodic orbits of singularly perturbed systems
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作者 Xiang Zhang 《中国科学:数学英文版》 SCIE CSCD 2019年第9期1687-1704,共18页
The main aims of this paper are to study the persistence of homoclinic and heteroclinic orbits of the reduced systems on normally hyperbolic critical manifolds, and also the limit cycle bifurcations either from the ho... The main aims of this paper are to study the persistence of homoclinic and heteroclinic orbits of the reduced systems on normally hyperbolic critical manifolds, and also the limit cycle bifurcations either from the homoclinic loop of the reduced systems or from a family of periodic orbits of the layer systems. For the persistence of homoclinic and heteroclinic orbits, and the limit cycles bifurcating from a homolinic loop of the reduced systems, we provide a new and readily detectable method to characterize them compared with the usual Melnikov method when the reduced system forms a generalized rotated vector field. To determine the limit cycles bifurcating from the families of periodic orbits of the layer systems, we apply the averaging methods.We also provide two four-dimensional singularly perturbed differential systems, which have either heteroclinic or homoclinic orbits located on the slow manifolds and also three limit cycles bifurcating from the periodic orbits of the layer system. 展开更多
关键词 singular PERTURBATION HOMOCLINIC and HETEROCLINIC ORBITS limit cycle rotating vector fields AVERAGING method
Stationary response of stochastic viscoelastic system with the right unilateral nonzero offset barrier impacts
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作者 王德莉 徐伟 谷旭东 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第1期195-204,共10页
The stationary response of viscoelastic dynamical system with the right unilateral nonzero offset barrier impacts subjected to stochastic excitations is investigated. First, the viscoelastic force is approximately tre... The stationary response of viscoelastic dynamical system with the right unilateral nonzero offset barrier impacts subjected to stochastic excitations is investigated. First, the viscoelastic force is approximately treated as equivalent terms associated with effects. Then, the free vibro-impact(VI) system is absorbed to describe the periodic motion without impacts and quasi-periodic motion with impacts based upon the level of system energy. The stochastic averaging of energy envelope(SAEE) is adopted to seek the stationary probability density functions(PDFs). The detailed theoretical results for Van der Pol viscoelastic VI system with the right unilateral nonzero offset barrier are solved to demonstrate the important effects of the viscoelastic damping and nonzero rigid barrier impacts condition. Monte Carlo(MC) simulation is also performed to verify the reliability of the suggested approach. The stochastic P-bifurcation caused by certain system parameters is further explored. The variation of elastic modulus from negative to zero and then to positive witnesses the evolution process of stochastic P-bifurcation. From the vicinity of the common value to a wider range, the relaxation time induces the stochastic P-bifurcation in the two interval schemes. 展开更多
关键词 viscoelastic system RIGHT UNILATERAL nonzero offset BARRIER IMPACTS STOCHASTIC AVERAGING of energy envelope(SAEE) STOCHASTIC P-bifurcation
New characterizations of Musielak-Orlicz-Sobolev spaces via sharp ball averaging functions
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作者 Sibei YANG Dachun YANG Wen YUAN 《中国数学前沿:英文版》 SCIE CSCD 2019年第1期177-201,共25页
We establish a new characterization of the Musielak-Orlicz-Sobolev space on ?n, which includes the classical Orlicz-Sobolev space, the weighted Sobolev space, and the variable exponent Sobolev space as special cases, ... We establish a new characterization of the Musielak-Orlicz-Sobolev space on ?n, which includes the classical Orlicz-Sobolev space, the weighted Sobolev space, and the variable exponent Sobolev space as special cases, in terms of sharp ball averaging functions. Even in a special case, namely, the variable exponent Sobolev space, the obtained result in this article improves the corresponding result obtained by P. H?st? and A. M. Ribeiro [Commun. Contemp. Math., 2017, 19: 1650022] via weakening the assumption f ∈ L^1(R^n) into f ∈ L^1loc(R^n), which was conjectured to be true by Hosto and Ribeiro in the aforementioned same article. 展开更多
关键词 Musielak-Orlicz-Sobolev SPACE Orlicz-Sobolev SPACE variable EXPONENT Sobolev SPACE SHARP BALL AVERAGING function
Stochastic averaging technique for SDOF strongly nonlinear systems with delayed feedback fractional-order PD controller
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作者 CHEN LinCong LIANG Xiao +1 位作者 ZHU WeiQiu ZHAO YaoBing 《中国科学:技术科学英文版》 SCIE EI CAS CSCD 2019年第2期287-297,共11页
A stochastic averaging technique is proposed to study the randomly excited single-degree-of-freedom(SDOF) strongly nonlinear systems with delayed feedback fractional-order proportional-derivative(PD) controller. The d... A stochastic averaging technique is proposed to study the randomly excited single-degree-of-freedom(SDOF) strongly nonlinear systems with delayed feedback fractional-order proportional-derivative(PD) controller. The delayed feedback fractional-order PD control force is approximated by an equivalent non-delay feedback control force combining with a quasi-linear elastic force and a quasi-linear damping force. The averaged It? stochastic differential equation for amplitude of the equivalent nonlinear system is derived by the generalized harmonic functions. The analytical stationary probability density function(PDF) is obtained with solving the reduced Fokker-Planck-Kolmogorov(FPK) equation. Two examples of van der Pol oscillator and RayleighDuffing oscillator are studied to illustrate the application and effectiveness of the proposed method. Numerical results display that the proposed method can yield to the high precision, and the time delay could ruin the control effectiveness, but also even amplifies the response of the system more than that of uncontrolled system. Furthermore, the study finds that the parameters of fractional-order α and time delay may cause the stochastic P-bifurcation. It is indicated that the delayed feedback fractional-order PD controller can offer a potentially effective tool for anti-control of stochastic bifurcation. 展开更多
关键词 αstochastic AVERAGING STRONGLY nonlinear system time DELAY FRACTIONAL-ORDER PD~a CONTROLLER
基于平均法的单自由度非线性系统幅频分析
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作者 王树国 郭丽峰 +1 位作者 廖鹏泰 张艳波 《机械强度》 CAS CSCD 北大核心 2019年第2期303-308,共6页
利用改进的平均法对振动微分方程进行了近似求解,得到了幅频响应方程,运用约束分岔理论对非线性系统进行了分析,计算了转迁集,得到了系统在阻尼比与激励振幅平面内不同区域的幅频曲线图,并对其特性进行了分析;其次,对幅频响应方程进行... 利用改进的平均法对振动微分方程进行了近似求解,得到了幅频响应方程,运用约束分岔理论对非线性系统进行了分析,计算了转迁集,得到了系统在阻尼比与激励振幅平面内不同区域的幅频曲线图,并对其特性进行了分析;其次,对幅频响应方程进行了局部线性化,应用线性系统理论得到了系统的稳定区域;最后分析了不同参数对系统的隔振效果,得到了阻尼比的增加会减弱系统的振动,加强隔振效果。 展开更多
关键词 平均法 非线性 幅频 稳定性
Research on the Error Averaging Effect in A Rolling Guide Pair 预览
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作者 Yanbing Ni Haiyang Zhou +1 位作者 Cuiyan Shao Jinhe Li 《中国机械工程学报:英文版》 SCIE EI CAS CSCD 2019年第4期104-115,共12页
By studying the e ects of geometric precision on kinematic accuracy, an error mapping model has been established, based on the hypothesis that a motion pair and its installation surface are rigid. However, when using ... By studying the e ects of geometric precision on kinematic accuracy, an error mapping model has been established, based on the hypothesis that a motion pair and its installation surface are rigid. However, when using this assumption,there is a significant error induced in high-precision computer numerical control(CNC) machine tools as compared with reality. One of the most important reasons for this error is failing to consider the error averaging e ect of motion pair elements. Therefore, this work examines a high-precision horizontal machining center as its research object, and analyzes the error averaging mechanism of a rolling guide pair under a deformation of the rolling elements. The carriage bearing forces caused by guideway straightness errors are obtained by constructing a geometric error model of a single carriage. The relationship between guideway straightness errors and carriage bearing forces is described by a transfer function in the spatial frequency domain, and its characteristics are analyzed. It quantifies the so-called error averaging e ect of the rolling guide system and, on this basis, a static model for four carriages is established to reflect the error averaging e ect of the rolling guide pair on the position and orientation errors of the motion pair. In addition, it is found that the wavelengths and phase di erences of guideway errors a ect this error averaging mechanism, but the amplitude and preload have little influence thereon. The experiment result shows that the kinematic straightness errors in the x-and y-directions were approximately 1/3 to 1/2 of the guideway straightness errors in the corresponding directions. The results can be used to guide the precision design and assembly of machine tools. 展开更多
关键词 Rolling guide PAIR ERROR AVERAGING mechanism GUIDEWAY STRAIGHTNESS ERRORS Precision design
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Travel time prediction with viscoelastic traffic model 预览
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作者 Yongliang ZHANG M.N.SMIRNOVA +2 位作者 A.I.BOGDANOVA Zuojin ZHU N.N.SMIRNOV 《应用数学和力学:英文版》 SCIE EI CSCD 2018年第12期1769-1788,共20页
Travel time through a ring road with a total length of 80 km has been predicted by a viscoelastic traffic model(VEM),which is developed in analogous to the non-Newtonian fluid flow.The VEM expresses a traffic pressure... Travel time through a ring road with a total length of 80 km has been predicted by a viscoelastic traffic model(VEM),which is developed in analogous to the non-Newtonian fluid flow.The VEM expresses a traffic pressure for the unfree flow case by space headway,ensuring that the pressure can be determined by the assumption that the relevant second critical sound speed is exactly equal to the disturbance propagation speed determined by the free flow speed and the braking distance measured by the average vehicular length.The VEM assumes that the sound speed for the free flow case depends on the traffic density in some specific aspects,which ensures that it is exactly identical to the free flow speed on an empty road.To make a comparison,the open Navier-Stokes type model developed by Zhang(ZHANG,H.M.Driver memory,traffic viscosity and a viscous vehicular traffic flow model.Transp.Res.Part B,37,27–41(2003))is adopted to predict the travel time through the ring road for providing the counterpart results.When the traffic free flow speed is 80 km/h,the braking distance is supposed to be 45m,with the jam density uniquely determined by the average length of vehicles l t 5.8m.To avoid possible singular points in travel time prediction,a distinguishing period for time averaging is pre-assigned to be 7.5 minutes.It is found that the travel time increases monotonically with the initial traffic density on the ring road.Without ramp effects,for the ring road with the initial density less than the second critical density,the travel time can be simply predicted by using the equilibrium speed.However,this simpler approach is unavailable for scenarios over the second critical. 展开更多
关键词 TRAVEL TIME VISCOELASTIC modeling distinguishing period for TIME AVERAGING spatial-temporal pattern TRAFFIC JAM
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A Semi-Analytical Method for the PDFs of A Ship Rolling in Random Oblique Waves 预览
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作者 LIU Li-qin LIU Ya-liu +2 位作者 XU Wan-hai LI Yan TANG You-gang 《中国海洋工程:英文版》 SCIE EI CSCD 2018年第1期74-84,共11页
The PDFs (probability density functions) and probability of a ship rolling under the random parametric and forced excitations were studied by a semi-analytical method. The rolling motion equation of the ship in random... The PDFs (probability density functions) and probability of a ship rolling under the random parametric and forced excitations were studied by a semi-analytical method. The rolling motion equation of the ship in random oblique waves was established. The righting arm obtained by the numerical simulation was approximately fitted by an analytical function. The irregular waves were decomposed into two Gauss stationary random processes, and the CARMA (2, 1) model was used to fit the spectral density function of parametric and forced excitations. The stochastic energy envelope averaging method was used to solve the PDFs and the probability. The validity of the semi-analytical method was verified by the Monte Carlo method. The C11 ship was taken as an example, and the influences of the system parameters on the PDFs and probability were analyzed. The results show that the probability of ship rolling is affected by the characteristic wave height, wave length, and the heading angle. In order to provide proper advice for the ship's manoeuvring, the parametric excitations should be considered appropriately when the ship navigates in the oblique seas. 展开更多
关键词 ship RANDOM rolling PARAMETRIC and FORCED excitations stochastic energy ENVELOPE AVERAGING method probability density function parameter influence analysis
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Effects of Power Inversion Spatial Only Adaptive Array on GNSS Receiver Measurements
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作者 Hailong Xu Xiaowei Cui Mingquan Lu 《清华大学学报:自然科学英文版》 EI CAS CSCD 2018年第2期172-183,共12页
The Spatial Only Processing Power Inversion (SOP-PI) algorithm is frequently used in Global NavigationSatellite System (GNSS) adaptive array receivers for interference mitigation because of its simplicity ofimplem... The Spatial Only Processing Power Inversion (SOP-PI) algorithm is frequently used in Global NavigationSatellite System (GNSS) adaptive array receivers for interference mitigation because of its simplicity ofimplementation. This study investigates the effects of SOP-PI on receiver measurements for high-precisionapplications. Mathematical deductions show that if an array with a centro-symmetrical geometry is used, ideally,SOP-PI is naturally bias-free; however, this no longer stands when non-ideal factors, including array perturbationsand finite-sample effect, are added. Simulations are performed herein to investigate how exactly the arrayperturbations affect the carrier phase biases, while diagonal loading and forward-backward averaging are proposedto counter the finite-sample effect. In conclusion, whether SQP-PI with a centro-symmetrical array geometry willsatisfy the high precision demands mainly depends on the array perturbation degree of the element amplitude andthe phase center. 展开更多
关键词 Global Navigation Satellite System (GNSS) receiver adaptive ARRAY HIGH-PRECISION application powerinversion measurement bias ARRAY perturbation DIAGONAL loading FORWARD-BACKWARD AVERAGING
Trace fossils of an amalgamated storm-bed succession from the Jurassic of the Kachchh Basin,India:The significance of time-averaging in ichnology
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作者 Franz To Fürsich Alfred Uchman +1 位作者 Matthias Alberti Dhirendra K.Pandey 《古地理学报:英文版》 CSCD 2018年第1期14-31,共18页
The uppermost part of the Upper Bathonian Sponge Limestone member, Patcham Formation, of the Jhura Dome of Kachchh Mainland is a thickening-and shallowing-upward succession topped by medium-to thick-bedded hummocky cr... The uppermost part of the Upper Bathonian Sponge Limestone member, Patcham Formation, of the Jhura Dome of Kachchh Mainland is a thickening-and shallowing-upward succession topped by medium-to thick-bedded hummocky cross-stratified grainstones deposited by storm waves. Occasionally, thin, commonly lenticular, intraclastic-bioclastic silty marl intercalations between the grainstones are highly bioturbated, in contrast to the grainstones, in which, for the most part, trace fossils occur scattered. Large exposures of bedding planes of the grainstones allow the detailed investigation of ichnological features, whereas the high density of traces in the soft marls precludes the identification of any ichnotaxa. Eighteen ichnotaxa have been recorded including Ophiomorpha, Thalassinoides, Taenidium, Gyrophyllites, Chondrites, Dactyloidites, Teichichnus, Bolonia, and Ancorichnus. Except for Ophiomorpha nodosa and Thalassinoides, which generally indicate moderate to high energy conditions and are the dwelling burrows of suspension-feeding to omnivorous crustaceans, the ichnotaxa represent a deposit-feeding behaviour of their producers and thus are characteristic of low-energy environments. The trace fossils form three ichnoassemblages characterized by(1) Ophiomorpha nodosa and Thalassinoides suevicus,(2)?Thalassinoides isp. A, Taenidium, and Bolonia lata,and(3) Ancorichnus. The dominance of traces of deposit-feeders in rocks indicative of high-energy events is counterintuitive and points to their non-contemporaneity. The sediments were deposited during brief highenergy events, whereas the trace fossils were produced when, after waning of storms low-energy conditions prevailed. This time-averaging is particularly pronounced in trace fossils that extend vertically downwards and may reach strata deposited under distinctly different conditions. Thus, environmental interpretations based on trace fossils should refer to colonisation surfaces rather than to the sediment surrounding the trace fossils. In the latter case, interpretat 展开更多
关键词 Trace FOSSILS Middle JURASSIC KACHCHH Basin Taxonomy TIME AVERAGING ICHNOLOGY
Near-Term Projections of Global and Regional Land Mean Temperature Changes Considering Both the Secular Trend and Multidecadal Variability
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作者 Yajie QI Zhongwei YAN +1 位作者 Cheng QIAN Ying SUN 《气象学报:英文版》 SCIE CSCD 2018年第3期337-350,共14页
Near-term climate projections are needed by policymakers; however, these projections are difficult because intern-ally generated climate variations need to be considered. In this study, temperature change scenarios in... Near-term climate projections are needed by policymakers; however, these projections are difficult because intern-ally generated climate variations need to be considered. In this study, temperature change scenarios in the near-termperiod 2017-35 are projected at global and regional scales based on a refined multi-model ensemble approach thatconsiders both the secular trend (ST) and multidecadal variability (MDV) in the Coupled Model IntercomparisonProject Phase 5 (CMIP5) simulations. The ST and MDV components are adaptively extracted from each model simu-lation by using the ensemble empirical mode decomposition (EEMD) filter, reconstructed via the Bayesian model av-eraging (BMA) method for the historical period 1901-2005, and validated for 2006-16. In the simulations of the"medium" representative concentration pathways scenario during 2017-35, the MDV-modulated temperature changeprojected via the refined approach displays an increase of 0.44℃ (90% uncertainty range from 0.30 to 0.58℃) forglobal land, 0.48℃ (90% uncertainty range from 0.29 to 0.67℃) for the Northern Hemispheric land (NL), and0.29℃ (90% uncertainty range from 0.23 to 0.35℃) for the Southern Hemispheric land (SL). These increases aresmaller than those projected by the conventional arithmetic mean approach. The MDV enhances the ST in 13 of 21regions across the world. The largest MDV-modulated warming effect (46%) exists in central America. In contrast,the MDV counteracts the ST in NL, SL, and eight other regions, with the largest cooling effect (220%) in Alaska. 展开更多
关键词 NEAR-TERM projection multidecadal variability MULTI-MODEL ENSEMBLE method ENSEMBLE empirical modedecomposition (EEMD) BAYESIAN model AVERAGING (BMA)
Stochastic averaging of quasi partially integrable Hamiltonian systems under fractional Gaussian noise
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作者 Qiang-feng LU Mao-lin DENG Wei-qiu ZHU 《浙江大学学报:A卷英文版》 SCIE EI CAS CSCD 2017年第9期704-717,共14页
A stochastic averaging method for predicting the response of quasi partially integrable and non-resonant Hamiltoniansystems to fractional Gaussian noise (fGla) with the Hurst index 1/2〈H〈l is proposed. The average... A stochastic averaging method for predicting the response of quasi partially integrable and non-resonant Hamiltoniansystems to fractional Gaussian noise (fGla) with the Hurst index 1/2〈H〈l is proposed. The averaged stochastic differential equa-tions (SDEs) for the first integrals of the associated Hamiltonian system are derived. The dimension of averaged SDEs is less thanthat of the original system. The stationary probability density and statistics of the original system are obtained approximately fromsolving the averaged SDEs numerically. Two systems are worked out to illustrate the proposed stochastic averaging method. It isshown that the results obtained by using the proposed stochastic averaging method and those from digital simulation of originalsystem agree well, and the computational time for the former results is less than that for the latter ones. 展开更多
关键词 FRACTIONAL BROWNIAN motion (fBm) FRACTIONAL Gaussian noise (fGn) QUASI PARTIALLY INTEGRABLE Hamiltonian system Stochastic AVERAGING method Stationary response
基于局部位移校正的磁共振图像相干平均 预览 被引量:1
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作者 李文静 谢海滨 +3 位作者 严序 周敏雄 向之明 杨光 《波谱学杂志》 CSCD 北大核心 2017年第3期294-301,共8页
多次扫描相干平均是提高磁共振图像信噪比的常用方法,但如果在多次扫描过程中病人发生自主或不自主的运动,使得图像中的组织发生位移,简单相干平均图像会导致图像模糊.本文受非局域均值算法的启发,提出了一种基于局部位移校正的相... 多次扫描相干平均是提高磁共振图像信噪比的常用方法,但如果在多次扫描过程中病人发生自主或不自主的运动,使得图像中的组织发生位移,简单相干平均图像会导致图像模糊.本文受非局域均值算法的启发,提出了一种基于局部位移校正的相干平均方法.该算法通过比较多次采集的图像中组织结构的局部相似性,找出图像间的局部位移,利用该信息修正位移后进行加权平均,从而达到提高图像信噪比的目的.我们用模型及真实的肝脏弥散数据进行了实验.实验结果表明,对于不同次采样间存在运动的磁共振图像,该算法可有效地提高信噪比并保持结构边缘;其结果优于简单的相干平均,去噪效果也优于经典的非局域均值算法. 展开更多
关键词 磁共振成像(MRI) 相干平均 非局域均值 图像去噪
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A Self-determined Evaluation Method for Science Popularization Based on IOWA Operator and Particle Swarm Optimization 预览
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作者 Tianlei Zang Yan Wang +1 位作者 Zhengyou He Qingquan Qian 《国际计算机前沿大会会议论文集》 2016年第1期27-29,共3页
With the increase of science popularization, evaluation of science popularization has become an urgent demand. Considering science popularization bases as independent agents, a self-determined evaluation approach for ... With the increase of science popularization, evaluation of science popularization has become an urgent demand. Considering science popularization bases as independent agents, a self-determined evaluation approach for science popularization using induced ordered weighted averaging (IOWA) operator and particle swarm optimization (PSO) is proposed in this paper.Firstly, six factors including science popularization personnel, space, fund,media, activity and influence are selected to construct an index system for science popularization evaluation. On this basis, the absolute dominance and relative dominance of evaluation indexes are used as induced components, and the prior order of the evaluation indexes is determined. Besides, the optimization model of index weighted vectors is established by IOWA operator, index weighted vectors are calculated by particle swarm optimization algorithm, and index weighted vectors and evaluation value vectors are obtain. Finally, the optimal evaluation vectors and evaluation results are given according to the Perron-Frobenius decision eigenvalve theorem . 展开更多
关键词 Science POPULARIZATION Self-determined evaluation Induced ORDERED Weighted AVERAGING operator Particle SWARM optimization Perron-Frobenius decision eigenvalve theorem
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An intra-cavity absorption fiber gas sensor based on performanceenhanced techniques 预览
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作者 LI Mo1 YANG Fan +1 位作者 LUO Yanhua PENG Gangding 《太赫兹科学与电子信息学报》 2015年第4期653-658,共6页
The performance of an erbium-doped fiber ring laser based intra-cavity absorption gassensor was evaluated with performance enhanced techniques. A multi-line wavelength sweep techniqueand a weighted averaging technique... The performance of an erbium-doped fiber ring laser based intra-cavity absorption gassensor was evaluated with performance enhanced techniques. A multi-line wavelength sweep techniqueand a weighted averaging technique were proposed for better gas detection. By selecting appropriatesystem parameters, 6 strong absorption lines near 1 530 nm of C2H2 were obtained with good spectrumresolution in one scanning period. One group with higher absorption coefficients was used for relativelylow gas concentration detection and the other with lower absorption coefficients was used for relativelyhigh gas concentration. Both the groups can be used for medium gas concentration detection. For variousconcentration cases, by choosing proper absorption lines and performing weighted averaging, detectionaccuracy can be obtained over an extended detection range. The minimum detection limit could be verylow after optimization. 展开更多
关键词 FIBER gas sensor intra-cavity ABSORPTION SPECTROSCOPY multi-line WAVELENGTH sweeptechnique WEIGHTED AVERAGING techni
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A 6-bit 2 GS/s ADC in 65 nm CMOS 被引量:1
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作者 WANG HaoNan WANG Tao +2 位作者 YAO YuFeng WANG Hui CHENG YuHua 《中国科学:信息科学(英文版)》 SCIE EI 2014年第6期290-294,共5页
A 6-bit 2 GS/s ADC was implemented using a 65 nm digital CMOS technology.The design is based on a single-channel flash ADC architecture,and utilizes interpolating and averaging techniques.A two-stage CML-CMOS high-spe... A 6-bit 2 GS/s ADC was implemented using a 65 nm digital CMOS technology.The design is based on a single-channel flash ADC architecture,and utilizes interpolating and averaging techniques.A two-stage CML-CMOS high-speed hybrid comparator is designed for optimal speed and power performance.The total power consumption of the converter is 52 mW and the area is 0.24 mm2.The ADC achieves 42.5 dB SFDR and5.2 bit ENOB at input frequency of 123 MHz,and at Nyquist frequency 37.67 dB SFDR and 4.9 bit ENOB. 展开更多
关键词 CMOS工艺 ADC 纳米 GS 奈奎斯特频率 SFDR 体系结构 动力性能
Approximate Kepler’s Elliptic Orbits with the Relativistic Effects 预览
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作者 Leilei Jia 《天文学与天体物理学国际期刊(英文)》 2013年第1期29-33,共5页
Beginning with a Lagrangian, we derived an approximate relativistic orbit equation which describes relativistic corrections to Keplerian orbits. The critical angular moment to guarantee the existence of periodic orbit... Beginning with a Lagrangian, we derived an approximate relativistic orbit equation which describes relativistic corrections to Keplerian orbits. The critical angular moment to guarantee the existence of periodic orbits is determined. An approximate relativistic Kepler’s elliptic orbit is illustrated by numerical simulation via a second-order perturbation method of averaging. 展开更多
关键词 Kepler’s ELLIPTIC ORBITS The RELATIVISTIC KEPLER Problem Unboundedness AVERAGING
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树木年轮轮宽年表建立方法研究进展 被引量:6
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作者 彭小梅 肖生春 肖洪浪 《中国沙漠》 CSCD 北大核心 2013年第3期857-865,共9页
树木年轮以其高分辨率、准确定年、样本广泛分布且可定量等优点,在全球变化特别是气候变化研究中广泛运用。去除以生长趋势为主的噪音,建立包含所需气候信息的轮宽年表是开展树木年轮气候学研究的关键。基于轮宽年表建立理论和树木径向... 树木年轮以其高分辨率、准确定年、样本广泛分布且可定量等优点,在全球变化特别是气候变化研究中广泛运用。去除以生长趋势为主的噪音,建立包含所需气候信息的轮宽年表是开展树木年轮气候学研究的关键。基于轮宽年表建立理论和树木径向生长概念模型,本文综述了轮宽年表建立过程中生长趋势拟合、指数化和均值化3个阶段的主要理论方法的研究进展;并详细介绍了最为关键的生长趋势拟合方法中,目前较为传统的曲线拟合类方法,和近20年来为克服曲线拟合类方法低频信息保留问题而受到关注和发展的区域曲线类方法;认为如何准确提取轮宽低频气候信息,将是树木年轮轮宽年表建立的主要发展趋势。 展开更多
关键词 轮宽年表 生长趋势拟合 去趋势 指数化 均值化
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