检索结果-南通市图书馆

Acta Mathematicae Applicatae Sinica 2022年第1期38卷 68-77页

作者： Souad BOUGUESSA Djillali BOUAGADA Mohammed Amine GHEZZAR Department of Mathematics and Computer Science ACSY Team-Laboratory of Pure and Applied Mathe-maticsAbdelhamid Ibn Badis University MostaganemP.O.Box 227/118University of Mostaganem27000 MostaganemAlgeria

The effectiveness of this paper lies in the influence of the discretization step on the asymptotic stability of the positive two-dimensional fractional linear systems.It aims at investigating whether,how and when this step affects the asymptotically stable two-dimensional positive fractional linear continuous-discrete systems.To accomplish this study,a new test was outlined and used so that the asymptotic stability of the system was measured both before and after being exposed to the sampling step.Furthermore,the conditions of that stability were assessed.As a result,the outcome of the approximation shows that the stability is preserved under a particular set of conditions.On this basis,the newly proposed approach is recommended for testing the intended stability of such systems.A numerical example is tested to show the accuracy and the applicability of the proposed tests.

关键词： discretization positivity stability two-dimensional systems

Monocular 3D gaze estimation using feature discretization and attention mechanism

在线全文

学校读者我要写书评

暂无评论

Optoelectronics Letters 2023年第5期19卷 301-306页

作者： SHA Tong SUN Jinglin PUN Siohang LIU Yu School of Microelectronics Tianjin UniversityTianjin 300072China Institute of Microelectronics University of MacaoMacao 999078China

Gaze estimation has become an important field of image and information processing.Estimating gaze from full-face images using convolutional neural network(CNN) has achieved fine accuracy.However,estimating gaze from eye images is very challenging due to the less information contained in eye images than in full-face images,and it’s still vital since eye-image-based methods have wider applications.In this paper,we propose the discretization-gaze network(DGaze-Net) to optimize monocular three-dimensional(3D) gaze estimation accuracy by feature discretization and attention mechanism.The gaze predictor of DGaze-Net is optimized based on feature discretization.By discretizing the gaze angle into K bins,a classification constraint is added to the gaze predictor.In the gaze predictor,the gaze angle is pre-applied with a binned classification before regressing with the real gaze angle to improve gaze estimation accuracy.In addition,the attention mechanism is applied to the backbone to enhance the ability to extract eye features related to gaze.The proposed method is validated on three gaze datasets and achieves encouraging gaze estimation accuracy.

关键词： estimation mechanism discretization

A robust discretization method of factor screening for landslide susceptibility mapping using convolution neural network,random forest,and logistic regression models

在线全文

学校读者我要写书评

暂无评论

International Journal of Digital Earth 2023年第1期16卷 408-429页

作者： Zheng Zhao Jianhua Chen State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijingPeople’s Republic of China University of Chinese Academy of Sciences BeijingPeople’s Republic of China College of Geophysics Chengdu University of TechnologyChengduPeople’s Republic of China

The selection of discretization criteria and interval numbers of landslide-related environmental factors generally fails to quantitatively determine orfilter,resulting in uncertainties and limitations in the performance of machine learning(ML)methods for landslide susceptibility mapping(LSM).The aim of this study is to propose a robust discretization criterion(RDC)to quantify and explore the uncertainty and subjectivity of different discretization methods.The RDC consists of two steps:raw classification dataset generation and optimal dataset extraction.To evaluate the robustness of the proposed RDC method,Lushan County of Sichuan Province in China was chosen as the study area to generate the LSM based on three datasets(optimal dataset,original dataset with continuous values,and statistical dataset)using three popular ML methods,namely,convolution neural network,random forest,and logistic regression.The results show that the areas under the receiver operating characteristic curve(AUCs)of the optimal dataset for the abovementioned ML models are 0.963,0.961,and 0.930 which are higher than those of the original dataset(0.938,0.947,and 0.900)and statistical dataset(0.948,0.954,and 0.897).In conclusion,the RDC method can extract the more representative features from environmental factors and outperform the other conventional discretization methods.

关键词： discretization machine learning landslide susceptibility mapping spatial statistics convolution neural network

Physiological and cognitive discontinuities:From mythical mediation to implicit discretization of architectural design tools

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Architectural Research 2023年第1期12卷 1-14页

作者： Damien Claeys Louvain Research Institute for Landscape ArchitectureBuilt Environment(LAB)and Faculty of ArchitectureArchitectural Engineering and Urban Planning(LOCI)Universite´catholique de Louvain(UCLouvain)BrusselsBelgium

In architectural design,representation tools are often compared according to their alleged effects on the creativity of designers.Moreover,their mediating capacities are often mythicized,to such an extent that one might surmise the direct transmission of the mental images from the designer’s consciousness to an external representation.In this speculative essay,we demonstrate that the process of representation at work in architectural design originates from the designer’s consciousness natural cognitive ability,rather than from the use of a specific mediation tool between the designer and his environment,between the mentally constructed architectural project and its representation.The effects of any tool of representationdanalog or digitaldon our perceptual apparatus depend primarily on the cognitive mechanisms affecting the discontinuous flow of internal representations formed by our consciousness.In other words,we propose to shed a new light on these limitations through the heuristic modeling of an architectural project designer confronted with his own cognitive biases,and the limits of the representation processes.In the present essay,the discontinuities and uncertainties inherent to the processes of representation are reintegrate in the models.

关键词： Architecture Design Representation discretization Discontinuity Digital Analog Uncertainty

discretization of Preisach hysteresis model

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Central South University 2015年第12期22卷 4724-4730页

作者：安凯蔡国平 Shandong Aerospace Electro-technology Institute Department of Engineering Mechanics Shanghai Jiaotong University

In order to reduce the partial derivative errors in Preisach hysteresis model caused by inaccurate experimental data,the concept and correlative method of discretization of Preisach hysteresis model are proposed,the essential of which is to centralize the distribution density of Preisach hysteresis model in local region as an integral,which is defined as the weight of a certain point in that region.For the input composed of an ascending segment and a descending segment,a method to determine the initial weights together with an additional method to determine present weights is given according to the number of input ascending segments.If the number of input ascending segments increases,the weights of the corresponding points in updating rectangle are updated by adding the initial weights of corresponding points.A prominent advantage of discrete Preisach hysteresis model is its memory efficiency.Another advantage of discrete Preisach hysteresis model is that there is no function in the model,and thus,it can be expediently operated using a computer.By generalizing the above updating rectangle method to the continuous Preisach hysteresis model,identification method of distribution density can be given as well.

关键词： hysteresis discretization distribution density output

discretization of Coupled Map Lattices for a Stream Cipher

在线全文

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2011年第3期16卷 241-246页

作者：尹汝明袁坚杨秋华山秀明王希勤 Department of Electronic Engineering Tsinghua University

Coupled map lattices （CML） have been recently used to construct ciphers. However, the complicated operations on real numbers make these CML-based ciphers difficult to analyze. This paper presents a new stream cipher with the discretized CML which operates on binary numbers. When discretizing the CML, the effective network structure is explicitly preserved to improve the confusion and diffusion. The proposed cipher can be easily analyzed using proper cryptographic techniques and has good security. The cipher has a strict lower bound on the period length of 264 and its key setup scheme achieves enough diffusion. The keystreams pass all of the NIST statistical randomness tests and have good randomness properties. In addition the cipher is resistant to the guess-and-determine attack.

关键词： stream cipher coupled map lattices confusion and diffusion discretization statistical test

discretization Algorithm Based on Particle Swarm Optimization and Its Application in Attributes Reduction for Fault Data

在线全文

学校读者我要写书评

暂无评论

Journal of Shanghai Jiaotong university(Science) 2018年第5期23卷 691-695页

作者：郑波李彦锋付国忠 Aviation Engineering institution Civil Aviation Flight University of China Center for System Reliability and Safety School of Mechanical and Electrical EngineeringUniversity of Electronic Science and Technology of China

In order to increase the fault diagnosis efficiency and make the fault data mining be realized, the decision table containing numerical attributes must be discretized for further calculations. The discernibility matrix-based reduction method depends on whether the numerical attributes can be properly discretized or not.So a discretization algorithm based on particle swarm optimization(PSO) is proposed. Moreover, hybrid weights are adopted in the process of particles evolution. Comparative calculations for certain equipment are completed to demonstrate the effectiveness of the proposed algorithm. The results indicate that the proposed algorithm has better performance than other popular algorithms such as class-attribute interdependence maximization(CAIM)discretization method and entropy-based discretization method.

关键词： attributes discretization fault data reduction discernibility matrix particle swarm optimization(PSO) hybrid weight

An Algorithm for the discretization of an Ideal Projector

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2016年第5期29卷 1400-1410页

作者： JIANG Xue ZHANG Shugong LI Zhe Institute of Mathematics Key Laboratory of Symbolic Computation and Knowledge Engineering (Ministry of Education) Jilin University Department of Applied Mathematics School of Science Changchun University of Science and Technology

Ideal interpolation is a generalization of the univariate Hermite interpolation. It is well known that every univariate Hermite interpolant is a pointwise limit of some Lagrange interpolants.However, a counterexample provided by Shekhtman Boris shows that, for more than two variables,there exist ideal interpolants that are not the limit of any Lagrange interpolants. So it is natural to consider: Given an ideal interpolant, how to find a sequence of Lagrange interpolants(if any) that converge to it. The authors call this problem the discretization for ideal interpolation. This paper presents an algorithm to solve the discretization problem. If the algorithm returns "True", the authors get a set of pairwise distinct points such that the corresponding Lagrange interpolants converge to the given ideal interpolant.

关键词： discretization 理想的插值 Lagrange 插值

New method for discretization of continuous attributes in rough set theory

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2010年第2期21卷 250-253页

作者： Rong Cong Xiukun Wang Kai Li Nanhai Yang School of Electronic and Information Engineering Dalian University of Technology Dalian 116024 E R. China Education Technology Center Dalian Naval Academy Dalian 116018 P. R. China The 92538 Unit of PLA Dalian 116041 E R. China

A new method for discretization of continuous attributes is put forward to overcome the limitation of the traditional rough sets, which cannot deal with continuous attributes.The method is based on an improved algorithm to produce candidate cut points and an algorithm of reduction based on variable precision rough information entropy. With the guarantee of consistency of decision system, the method can reduce the number of cut points and im- prove efficiency of reduction. Adopting variable precision rough information entropy as measure criterion, it has a good tolerance to noise. Experiments show that the algorithm yields satisfying reduction results.

关键词： rough set discretization reduction

Numerical Analysis for an Energy-stable Total discretization of a Poromechanics Model with Inf-sup Stability

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2019年第1期35卷 28-53页

作者： B.BURTSCHELL P.MOIREAU D.CHAPELLE Inria Université Paris-Saclay LMS Ecole PolytechniqueCNRS

We consider a previously proposed general nonlinear poromechanical formulation, and we derive a linearized version of this model. For this linearized model, we obtain an existence result and we propose a complete discretization strategy – in time and space – with a special concern for issues associated with incompressible or nearly-incompressible behavior. We provide a detailed mathematical analysis of this strategy,the main result being an error estimate uniform with respect to the compressibility parameter. We then illustrate our approach with detailed simulation results and we numerically investigate the importance of the assumptions made in the analysis, including the fulfillment of specific inf-sup conditions.

关键词： poromechanics incompressibility total discretization inf-sup energy estimates