期刊文献+
共找到1,921篇文章
< 1 2 97 >
每页显示 20 50 100
A FORMAL REPRESENTATION FOR FEATURE-BASED DESIGN 被引量:1
1
作者 孙正兴 丁秋林 张福炎 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 1997年第1期37-46,共10页
Feature based design has been regarded as a promising approach for CAD/CAM integration.This paper aims to establish a domain independent representation formalism for feature based design in three aspects: formal re... Feature based design has been regarded as a promising approach for CAD/CAM integration.This paper aims to establish a domain independent representation formalism for feature based design in three aspects: formal representation,design process model and design algorithm.The implementing scheme and formal description of feature taxonomy,feature operator,feature model validation and feature transformation are given in the paper.The feature based design process model suited for either sequencial or concurrent engineering is proposed and its application to product structural design and process plan design is presented. Some general design algorithms for developing feature based design system are also addressed.The proposed scheme provides a formal methodology elementary for feature based design system development and operation in a structural way. 展开更多
关键词 CAD CAM product modelling design process feature based design representation formalism
下载PDF
A Feature-Based Parametric Product Modeling System in CIMS Environment 被引量:4
2
作者 李海龙 《High Technology Letters》 EI CAS 1997年第1期13-16,共4页
This paper proposes an approach of developing the feature based parametric product modeling system which is suitable for integrated engineering design in CIMS environment.The architecture of ZD--MCADII and the charact... This paper proposes an approach of developing the feature based parametric product modeling system which is suitable for integrated engineering design in CIMS environment.The architecture of ZD--MCADII and the characteristics of its each module are introduced in detail. ZD--MCADII’s product data is managed by an object--oriented database management system OSCAR, and the product model is built according to the standard STEP. The product design is established on a unified product model, and all the product data are globally associated in ZD--MCADII. ZD--MCADII provides various design features to facilitate the product design, and supports the integrity of CAD, CAPP and CAM. 展开更多
关键词 CIMS feature based modeling PARAMETRIC design PRODUCT model OODB
下载PDF
GENERATIVE CAPP APPROACH BASED ON RESOURCE MODEL AND FEATURE MODEL 被引量:1
3
作者 倪前富 戴国洪 +1 位作者 严隽琪 马登哲 《Journal of Shanghai Jiaotong university(Science)》 EI 1998年第1期47-53,共7页
GENERATIVECAPPAPPROACHBASEDONRESOURCEMODELANDFEATUREMODEL*NiQianfu(倪前富)DaiGuohong(戴国洪)YanJunqi(严隽琪)MaDengzhe... GENERATIVECAPPAPPROACHBASEDONRESOURCEMODELANDFEATUREMODEL*NiQianfu(倪前富)DaiGuohong(戴国洪)YanJunqi(严隽琪)MaDengzhe(马登哲)(Dept.ofMech... 展开更多
关键词 严隽琪 ON RESOURCE based MODEL feature APPROACH AND
下载PDF
Feature Selection for Image Classification Based on a New Ranking Criterion 被引量:1
4
作者 Xuan Zhou Jiajun Wang 《Journal of Computer and Communications》 2015年第3期74-79,共6页
In this paper, a feature selection method combining the reliefF and SVM-RFE algorithm is proposed. This algorithm integrates the weight vector from the reliefF into SVM-RFE method. In this method, the reliefF filters ... In this paper, a feature selection method combining the reliefF and SVM-RFE algorithm is proposed. This algorithm integrates the weight vector from the reliefF into SVM-RFE method. In this method, the reliefF filters out many noisy features in the first stage. Then the new ranking criterion based on SVM-RFE method is applied to obtain the final feature subset. The SVM classifier is used to evaluate the final image classification accuracy. Experimental results show that our proposed relief- SVM-RFE algorithm can achieve significant improvements for feature selection in image classification. 展开更多
关键词 feature SELECTION for IMAGE Classification based on a New RANKING CRITERION
下载PDF
Image block feature vectors based on a singular-value information metric and color-texture description 被引量:4
5
作者 王朔中 路兴 +1 位作者 苏胜君 张新鹏 《Journal of Shanghai University(English Edition)》 CAS 2007年第3期205-209,共5页
In this work, image feature vectors are formed for blocks containing sufficient information, which are selected using a singular-value criterion. When the ratio between the first two SVs axe below a given threshold, t... In this work, image feature vectors are formed for blocks containing sufficient information, which are selected using a singular-value criterion. When the ratio between the first two SVs axe below a given threshold, the block is considered informative. A total of 12 features including statistics of brightness, color components and texture measures are used to form intermediate vectors. Principal component analysis is then performed to reduce the dimension to 6 to give the final feature vectors. Relevance of the constructed feature vectors is demonstrated by experiments in which k-means clustering is used to group the vectors hence the blocks. Blocks falling into the same group show similar visual appearances. 展开更多
关键词 image feature COLOR TEXTURE content-based image retrieval (CBIR) image hashing
下载PDF
DIMENSION VARIATION OF FEATURE-BASED MODEL BY OPERATING DIRECTLY ON B-REP
6
作者 何小朝 王宗彦 +1 位作者 彭维 张铁昌 《Chinese Journal of Aeronautics》 SCIE EI CSCD 1998年第2期57-63,共7页
DIMENSIONVARIATIONOFFEATURE┐BASEDMODELBYOPERATINGDIRECTLYONB┐REPHEXiaozhao(何小朝),WANGZongyan(王宗彦)PENGWei(彭维),... DIMENSIONVARIATIONOFFEATURE┐BASEDMODELBYOPERATINGDIRECTLYONB┐REPHEXiaozhao(何小朝),WANGZongyan(王宗彦)PENGWei(彭维),ZHANGTiechang(张铁昌... 展开更多
关键词 design by feature CONSTRAINT feature based model dimension variation
下载PDF
Feature-based and objectoriented product information model for welding structure
7
作者 林三宝 杨春利 +1 位作者 黎明 吴林 《China Welding》 EI CAS 1999年第2期3-10,共8页
Product information model for welding structure plays an important role for the integration of welding CAD/CAPP/CAM. However, existing CAD modeling systems are not capable of providing enough information for subsequen... Product information model for welding structure plays an important role for the integration of welding CAD/CAPP/CAM. However, existing CAD modeling systems are not capable of providing enough information for subsequent manufacturing activities such as CAPP and CAM. A new design approach using feature technique and object oriented programming method is put forward in this paper in order to create the product information model of welding structure. With this approach, the product information model is able to effectively support computer aided welding process planning, fixturing, assembling, path planning of welding robot and other manufacturing activities. The feature classification and representing scheme of welding structure are discussed. A prototype system is developed based on feature and object oriented programming. Its structure and functions are given in detail. 展开更多
关键词 object oriented programming feature based design product information model welding structure CAD/CAM integration
下载PDF
Feature-Based Aggregation and Deep Reinforcement Learning:A Survey and Some New Implementations 被引量:14
8
作者 Dimitri P.Bertsekas 《IEEE/CAA Journal of Automatica Sinica》 EI CSCD 2019年第1期1-31,共31页
In this paper we discuss policy iteration methods for approximate solution of a finite-state discounted Markov decision problem, with a focus on feature-based aggregation methods and their connection with deep reinfor... In this paper we discuss policy iteration methods for approximate solution of a finite-state discounted Markov decision problem, with a focus on feature-based aggregation methods and their connection with deep reinforcement learning schemes. We introduce features of the states of the original problem, and we formulate a smaller "aggregate" Markov decision problem, whose states relate to the features. We discuss properties and possible implementations of this type of aggregation, including a new approach to approximate policy iteration. In this approach the policy improvement operation combines feature-based aggregation with feature construction using deep neural networks or other calculations. We argue that the cost function of a policy may be approximated much more accurately by the nonlinear function of the features provided by aggregation, than by the linear function of the features provided by neural networkbased reinforcement learning, thereby potentially leading to more effective policy improvement. 展开更多
关键词 REINFORCEMENT learning dynamic programming Markovian decision problems AGGREGATION feature-based ARCHITECTURES policy ITERATION DEEP neural networks rollout algorithms
下载PDF
Experimental validation of a signal-based approach for structural earthquake damage detection using fractal dimension of time frequency feature 被引量:2
9
作者 Tao Dongwang Mao Chenxi +1 位作者 Zhang Dongyu Li Hui 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2014年第4期671-680,共10页
This article extends a signal-based approach formerly proposed by the authors, which utilizes the fractal dimension of time frequency feature (FDTFF) of displacements, for earthquake damage detection of moment resis... This article extends a signal-based approach formerly proposed by the authors, which utilizes the fractal dimension of time frequency feature (FDTFF) of displacements, for earthquake damage detection of moment resist frame (MRF), and validates the approach with shaking table tests. The time frequency feature (TFF) of the relative displacement at measured story is defined as the real part of the coefficients of the analytical wavelet transform. The fractal dimension (FD) is to quantify the TFF within the fundamental frequency band using box counting method. It is verified that the FDTFFs at all stories of the linear MRF are identical with the help of static condensation method and modal superposition principle, while the FDTFFs at the stories with localized nonlinearities due to damage will be different from those at the stories without nonlinearities using the reverse-path methodology. By comparing the FDTFFs of displacements at measured stories in a structure, the damage-induced nonlinearity of the structure under strong ground motion can be detected and localized. Finally shaking table experiments on a 1:8 scale sixteen-story three-bay steel MRF with added frictional dampers, which generate local nonlinearities, are conducted to validate the approach. 展开更多
关键词 earthquake damage detection time frequency feature fractal dimension signal-based shaking table test frictional damper
下载PDF
Fast Image Retrieval of Textile Industrial Accessory Based on Multi-Feature Fusion
10
作者 沈文忠 杨杰 《Journal of Donghua University(English Edition)》 EI CAS 2004年第3期117-122,共6页
A hierarchical retrieval scheme of the accessory image database is proposed based on textile industrial accessory contour feature and region feature. At first smallest enclosed rectangle[1] feature (degree of accessor... A hierarchical retrieval scheme of the accessory image database is proposed based on textile industrial accessory contour feature and region feature. At first smallest enclosed rectangle[1] feature (degree of accessory coordination) is used to filter the image database to decouple the image search scope. After the accessory contour information and region information are extracted, the fusion multi-feature of the centroid distance Fourier descriptor and distance distribution histogram is adopted to finish image retrieval accurately. All the features above are invariable under translation, scaling and rotation. Results from the test on the image database including 1,000 accessory images demonstrate that the method is effective and practical with high accuracy and fast speed. 展开更多
关键词 content based retrieval smallest enclosed rectangle (SER) hierarchical retrieval Fourier descriptor feature fusion
下载PDF
PRODUCT IMAGE RETRIEVAL BASED ON CO-FEATURES OF THE OBJECT
11
作者 Fu Haiyan Kong Xiangwei t Yang Nan Zhou Jianhui Chu Fengtao 《Journal of Electronics(China)》 2010年第6期815-821,共7页
In this paper, we propose a product image retrieval method based on the object contour corners, image texture and color. The product image mainly highlights the object and its background is very simple. According to t... In this paper, we propose a product image retrieval method based on the object contour corners, image texture and color. The product image mainly highlights the object and its background is very simple. According to these characteristics, we represent the object using its contour, and detect the corners of contour to reduce the number of pixels. Every corner is described using its approximate curvature based on distance. In addition, the Block Difference of Inverse Probabilities (BDIP) and Block Variation of Local Correlation (BVLC) texture features and color moment are extracted from image's HIS color space. Finally, dynamic time warping method is used to match features with different length. In order to demonstrate the effect of the proposed method, we carry out experiments in Mi-crosoft product image database, and compare it with other feature descriptors. The retrieval precision and recall curves show that our method is feasible. 展开更多
关键词 Product image retrieval Multi-features Approximate curvature based on distance Block Difference of Inverse Probabilities (BDIP) and Block Variation of Local Correlation (BVLC) texture features Color moment
下载PDF
Identification of Question and Non-Question Segments in Arabic Monologues Using Prosodic Features: Novel Type-2 Fuzzy Logic and Sensitivity-Based Linear Learning Approaches
12
作者 Sunday Olusanya Olatunji Lahouari Cheded +1 位作者 Wasfi G. Al-Khatib Omair Khan 《Journal of Intelligent Learning Systems and Applications》 2013年第3期165-175,共11页
In this paper, we extend our previous study of addressing the important problem of automatically identifying question and non-question segments in Arabic monologues using prosodic features. We propose here two novel c... In this paper, we extend our previous study of addressing the important problem of automatically identifying question and non-question segments in Arabic monologues using prosodic features. We propose here two novel classification approaches to this problem: one based on the use of the powerful type-2 fuzzy logic systems (type-2 FLS) and the other on the use of the discriminative sensitivity-based linear learning method (SBLLM). The use of prosodic features has been used in a plethora of practical applications, including speech-related applications, such as speaker and word recognition, emotion and accent identification, topic and sentence segmentation, and text-to-speech applications. In this paper, we continue to specifically focus on the Arabic language, as other languages have received a lot of attention in this regard. Moreover, we aim to improve the performance of our previously-used techniques, of which the support vector machine (SVM) method was the best performing, by applying the two above-mentioned powerful classification approaches. The recorded continuous speech is first segmented into sentences using both energy and time duration parameters. The prosodic features are then extracted from each sentence and fed into each of the two proposed classifiers so as to classify each sentence as a Question or a Non-Question sentence. Our extensive simulation work, based on a moderately-sized database, showed the two proposed classifiers outperform SVM in all of the experiments carried out, with the type-2 FLS classifier consistently exhibiting the best performance, because of its ability to handle all forms of uncertainties. 展开更多
关键词 ARABIC Monologues Prosodic features Type-2 FUZZY LOGIC Systems Sensitivity based LINEAR LearningMethod Support Vector Machines
下载PDF
Integrating Color and Spatial Feature for Content-Based Image Retrieval 被引量:1
13
作者 Cao Kui Feng Yu-cai 《Wuhan University Journal of Natural Sciences》 EI CAS 2002年第3期290-296,共7页
In this paper, we present a novel and efficient scheme for extracting, indexing and retrieving color images. Our motivation was to reduce the space overhead of partition-based approaches taking advantage of the fact t... In this paper, we present a novel and efficient scheme for extracting, indexing and retrieving color images. Our motivation was to reduce the space overhead of partition-based approaches taking advantage of the fact that only a relatively low number of distinct values of a particular visual feature is present in most images. To extract color feature and build indices into our image database we take into consideration factors such as human color perception and perceptual range, and the image is partitioned into a set of regions by using a simple classifying scheme. The compact color feature vector and the spatial color histogram, which are extracted from the seqmented image region, are used for representing the color and spatial information in the image. We have also developed the region-based distance measures to compare the similarity of two images. Extensive tests on a large image collection were conducted to demonstrate the effectiveness of the proposed approach. 展开更多
关键词 color distribution spatial color histogram region-based image representation and retrieval similarity matching integrating of single features
下载PDF
The Feature-Based a New Object Coding Approach for Prismatic Parts at the Part Modeling
14
作者 Ismet Celik Ali Unuvar 《Modeling and Numerical Simulation of Material Science》 2013年第4期129-138,共10页
Use of features in order to achieve the integration of design and manufacture has been considered to be a key factor recent years. Features such as manufacturing properties form the workpiece. Features are structured ... Use of features in order to achieve the integration of design and manufacture has been considered to be a key factor recent years. Features such as manufacturing properties form the workpiece. Features are structured systematically through object oriented modeling. This article explains an object coding method developed for prismatic workpieces and the use of that method in process planning. Features have been determined and modeled as objects. Features have been coded according to their types and locations on the workpiece in this given method. Feature codings have been seen to be very advantageous in process planning. 展开更多
关键词 feature feature based Modeling Object Oriented Modeling Process Planning
下载PDF
Content-based facial image authentication via statistic features
15
作者 HAN Qi LI Qiong NIU Xia-mu 《通讯和计算机(中英文版)》 2009年第2期16-20,共5页
关键词 人脸图像 图像识别 计算机技术 图像处理
下载PDF
Colour Features Extraction Techniques and Approaches for Content-Based Image Retrieval (CBIR) System
16
作者 Muhammad Naim Abdullah Mohd Afizi Mohd Shukran +4 位作者 Mohd Rizal Mohd Isa Nor Suraya Mariam Ahmad Mohammad Adib Khairuddin Mohd Sidek Fadhil Mohd Yunus Fatimah Ahmad 《Journal of Materials Science and Chemical Engineering》 2021年第7期29-34,共6页
<div style="text-align:justify;"> An image retrieval system was developed purposely to provide an efficient tool for a set of images from a collection of images in the large database that matches the u... <div style="text-align:justify;"> An image retrieval system was developed purposely to provide an efficient tool for a set of images from a collection of images in the large database that matches the user’s requirements in similarity evaluations such as image content similarity, edge, and colour similarity. Retrieving images based on the contents which are colour, texture, and shape is called content-based image retrieval (CBIR). This paper discusses and describes about the colour features technique for image retrieval systems. Several colour features technique and algorithms produced by the previous researcher are used to calculate the similarity between extracted features. This paper also describes about the specific technique about the colour basis features and combined features (hybrid techniques) between colour and shape features. </div> 展开更多
关键词 Content-based Image Retrieval Colour features CBIR
下载PDF
Automated Pulse-Based Diagnosis: Role of TIM Diagnostic Features
17
作者 Rajani R. Joshi 《Journal of Biomedical Science and Engineering》 2014年第10期781-787,共7页
Emanated from the idea of reinvestigating ancient medical system of Ayurveda—Traditional Indian Medicine (TIM), our recent study had shown significant applications of analysis of arterial pulse waveforms for non-inva... Emanated from the idea of reinvestigating ancient medical system of Ayurveda—Traditional Indian Medicine (TIM), our recent study had shown significant applications of analysis of arterial pulse waveforms for non-invasive diagnosis of cardiovascular functions. Here we present results of further investigations analyzing the relation of pulse-characteristics with some clinical and pathological parameters and other features that are of diagnostic importance in Ayurveda. 展开更多
关键词 Pulse-based DIAGNOSIS Spectral Parameters TIM (Traditional Indian Medicine) DIAGNOSTIC featureS Statistical Analysis
下载PDF
Content-Based Lace Image Retrieval System Using a Hierarchical Multifeature Scheme
18
作者 曹霞 李岳阳 +2 位作者 罗海驰 蒋高明 丛洪莲 《Journal of Donghua University(English Edition)》 EI CAS 2016年第4期562-565,568,共5页
An android-based lace image retrieval system based on content-based image retrieval (CBIR) technique is presented. This paper applies shape and texture features of lace image in our system and proposes a hierarchical ... An android-based lace image retrieval system based on content-based image retrieval (CBIR) technique is presented. This paper applies shape and texture features of lace image in our system and proposes a hierarchical multifeature scheme to facilitate coarseto-fine matching for efficient lace image retrieval in a large database. Experimental results demonstrate the feasibility and effectiveness of the proposed system meet the requirements of realtime. 展开更多
关键词 Retrieval retrieval matching hierarchical texture CBIR Hierarchical registration facilitate preprocessing
下载PDF
CONSTRUCTION AND MODIFICATION OF FLEXIBLE FEATURE-BASED MODELS
19
作者 He Xiaozhao Zhang Tiechang Gao Guangtao CAD/CAM Research Center,Northwestern Polytechnical University 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 1999年第1期12-18,共7页
A new approach is proposed to generate flexible featrure based models (FFBM), which can be modified dynamically. BRep/CSFG/FRG hybrid scheme is used to describe FFBM, in which BRep explicitly defines the model, CSFG ... A new approach is proposed to generate flexible featrure based models (FFBM), which can be modified dynamically. BRep/CSFG/FRG hybrid scheme is used to describe FFBM, in which BRep explicitly defines the model, CSFG (Constructive solid feature geometry) tree records the feature based modelling procedure and FRG (Feature relation graph) reflects different knids of relationship among features. Topological operators with local retrievability are designed to implement feature addition, which is traced by topological operation list (TOL) in detail. As a result, FFBM can be modified directly in the system database. Related features' chain reactions and variable topologies are supported in design modification, after which the product information adhering on features will not be lost. Further, a feature can be modified as rapidly as it was added. 展开更多
关键词 Flexible design Topological operation list feature based model
全文增补中
Stability ofWorkpkce Setup in Feature-Based Fixture Planning System
20
作者 ShenXiaohong LiuXuan 《Computer Aided Drafting,Design and Manufacturing》 2002年第2期37-43,共7页
Analyzed the issues of stability of workpiece during clamping and machining. Discussed classification of the stability problem according to the forces acting on the part in the commonly used machining processes; gave ... Analyzed the issues of stability of workpiece during clamping and machining. Discussed classification of the stability problem according to the forces acting on the part in the commonly used machining processes; gave the methods of calculating clamping force and measures to guarantee the stability of workpiece in the feature-based fixture planning design system. 展开更多
关键词 feature-based design fixture planning stability algorithm
下载PDF
上一页 1 2 97 下一页 到第
使用帮助 返回顶部