A FORMAL REPRESENTATION FOR FEATURE-BASED DESIGN

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.

MRMR Based Feature Vector Design for Efficient Citrus Disease Detection

In recent times,the images and videos have emerged as one of the most important information source depicting the real time scenarios.Digital images nowadays serve as input for many applications and replacing the manual methods due to their capabilities of 3D scene representation in 2D plane.The capabilities of digital images along with utilization of machine learning methodologies are showing promising accuracies in many applications of prediction and pattern recognition.One of the application fields pertains to detection of diseases occurring in the plants,which are destroying the widespread fields.Traditionally the disease detection process was done by a domain expert using manual examination and laboratory tests.This is a tedious and time consuming process and does not suffice the accuracy levels.This creates a room for the research in developing automation based methods where the images captured through sensors and cameras will be used for detection of disease and control its spreading.The digital images captured from the field’s forms the dataset which trains the machine learning models to predict the nature of the disease.The accuracy of these models is greatly affected by the amount of noise and ailments present in the input images,appropriate segmentation methodology,feature vector development and the choice of machine learning algorithm.To ensure the high rated performance of the designed system the research is moving in a direction to fine tune each and every stage separately considering their dependencies on subsequent stages.Therefore the most optimum solution can be obtained by considering the image processing methodologies for improving the quality of image and then applying statistical methods for feature extraction and selection.The training vector thus developed is capable of presenting the relationship between the feature values and the target class.In this article,a highly accurate system model for detecting the diseases occurring in citrus fruits using a hybrid feature development approach is proposed.The overall improvement in terms of accuracy is measured and depicted.

Practice and Features of Neo-Chinese Style in Rural Landscape in Zhejiang Province

Neo-Chinese style is popular nowadays and it is wildly used in rural landscape,with only few theories.Under the background of rural revitalization,this paper discussed practice types and design features of neo-Chinese style in rural landscape.Some typical and famous villages of Ningbo,Quzhou and Lishui cities in Zhejiang Province were chosen as cases in this paper.It is committed to providing some theories,inheriting rural culture and promoting rural revitalization.

A FEATURE－BASED PRODUCT MODELLING SYSTEM ON PC （CASE STUDY OF PARTS DESIGN FOR PRESS MACHINE）

This article reports on the design and implementation of feature modelling system for the CAPP of rotational symmetric components. The work deals with design by features, feature parts database design, and parts information modelling techniques realized in Personal Computer. The modular software provides utilities such as interactive component synthesis, dimensioning, tolerancing and graphical display.

PERFORMANCE-BASED INTELLIGENT RESOURCE DESCRIPTION MODEL FOR INTERNET-BASED PRODUCT DESIGN

Issues on intelligent resource description and multiple intelligent resources integration for lntemet based collaborative design are analyzed. A performance-based intelligent resource description model for lnternet-based product design is proposed, which can help to create, store, manipulate and exchange intelligent resource description information for applications, tools and systems in Interact-based product design. A method to integrate multiple intelligent resources to fulfill a complex product design and analysis via lntemet is also proposed. A real project for improving the bearing system design of a turbo-expander with many intelligent resources in prominent universities is presented as a case study.

Research on Variable Structure Parametric Design System of Ceramic Tile Mould Based on Modular

To solve the existing problems during the ceramic mold enterprises product design and development process, the variable structure parametric design system based on modular of ceramic mold has been developed. The system uses the object-oriented technology and top-down design concept as a guide, establishes a ceramic mold parametric design process, divides the process of ceramic mold design into modules of different levels and creates a component model library based on the functional analysis. Expanding modular thinking to parts structure design level is an effective solution to the difficulty of changing the structure during the product design process. Examples show that the system can achieve a ceramic mold product design, improve design efficiency.

Feature-based and objectoriented product information model for welding structure

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.

DIMENSION VARIATION OF FEATURE-BASED MODEL BY OPERATING DIRECTLY ON B-REP

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REVERSE MODELING FOR CONIC BLENDING FEATURE

A novel method to extract conic blending feature in reverse engineering is presented. Different from the methods to recover constant and variable radius blends from unorganized points, it contains not only novel segmentation and feature recognition techniques, but also bias corrected technique to capture more reliable distribution of feature parameters along the spine curve. The segmentation depending on point classification separates the points in the conic blend region from the input point cloud. The available feature parameters of the cross-sectional curves are extracted with the processes of slicing point clouds with planes, conic curve fitting, and parameters estimation and compensation, The extracted parameters and its distribution laws are refined according to statistic theory such as regression analysis and hypothesis test. The proposed method can accurately capture the original design intentions and conveniently guide the reverse modeling process. Application examples are presented to verify the high precision and stability of the proposed method.

Influence of the cylinder head structure of a diesel engine on fatigue strength

Using finite element method,influence of diesel cylinder head structure on fatigue strength is investigated.A simplified head model with function characteristics is built for thermal-mechanical simulation.From the simulation results,the influence of valve bridge structure and roof transition fillet dimension on fatigue strength are obtained.And a new valve bridge structure which can effectively improve the fatigue life is proposed.

Tourism-guided Planning of Immigrant Relocation:A Case Study of Phoenix Mountain Resort Park in Hanyin County, South Shaanxi

The implementation of the rural resettlement policy in southern Shaanxi has produced a lot of rural immigrants that need urgent resettlement. The subsequent settlement problem is the core issue of migration policy. All kinds of special background and demand of these "rural immigrants" put forward new requirements for resettlement planning. This paper explored the planning of rural immigrant relocation under the guidance of tourism industry, so as to create a new living environment for immigrants inheriting traditional cultural context, and revitalize the new urbanization of south Shaanxi. First, the paper briefly introduced the background of the rural resettlement policy in south Shaanxi. Second, taking the Phoenix Mountain Resort Park in Hanyin County for example, this paper used SWOT to analyze the feasibility of immigrant relocation in comprehensive tourist service area. Third, this paper elaborated the specific concepts and schemes.

Modeling of Additive Manufacturing Process Relevant Feature in Layer Based Manufacturing Process Planning

Compared with general machining processes,additive manufacturing(AM) process has stabler planning route and limited process variables and this makes it to be more easily designed and planned with knowledge based systems and computer aided techniques.Case based reasoning approach is applied to the process planning of additive manufacturing in this paper.The concept of "AM process relevant design features" is proposed after the analysis of the characteristics of AM processes.The concept is used as the basis of the knowledge representation,and AM relevant feature graph is used as the case representation schema.The case retrieval method is discussed based on this graph.The case representation of a machine arm is given to illustrate the brief process of the proposed approach.

Hierarchical Geometric Constraint Model for Parametric Feature Based Modeling

A new geometric constraint model is described, which is hierarchical and suitable for parametric feature based modeling. In this model, different levels of geometric information are represented to support various stages of a design process. An efficient approach to parametric featu-re based modeling is also presented, adopting the high level geometric constraint model. The low level geometric model such as B-reps can be derived automatically from the high level geometric constraint model, enabling designers to perform their task of detailed design.

Overview of Research and Development Status of Brushless Doubly-Fed Machine System

The brushless doubly-fed machine(BDFM)has been widely used due to its advantages of robustness,reliable operation,ease of maintenance,adjustable power factor,small converter capacity and low cost.BDFM is attractive for use in many applications such as variable frequency speed regulation systems and variable speed constant frequency generation systems.Hence,there is a rapidly growing interest in design and control of BDFM.In this paper,the origin and development of BDFM are reviewed,the structural characteristics of BDFM are discussed at length,the principles of operation and design are analyzed,and the different control methods used for BDFM are overviewed and compared in detail.Finally,challenges and opportunities of BDFM are concluded.