N-Rep: A Neutral Feature Representation to Support Feature Mapping and Data Exchange Across Applications

2004 ◽  
Author(s):  
Madhu S. Medichalam ◽  
Jami J. Shah ◽  
Roshan D’Souza
Keyword(s):  
Data Exchange ◽  
Feature Recognition ◽  
Data Transfer ◽  
Feature Representation ◽  
Declarative Language ◽  
Feature Mapping ◽  
Topological Relationships ◽  
Feature Based ◽  
Parametric Relationships ◽  
Exchange Medium

The proliferation of different feature based systems has made feature data exchange an important issue. Unlike geometry data exchange, where different representations use the same fundamental concepts; the most popular being B-Rep and CSG [Shah et al. 88], different feature representation schemes use different concepts to represent features corresponding to the application and domain. Therefore, feature data transfer between applications not only involves transfer of instance data but also transformation of feature concepts. This paper presents N-Rep, an application independent declarative language, for feature definition that includes topology, topological relationships, geometry, geometric relationships, parameters and parametric relationships. N-Rep has been designed to serve three roles, viz., (a) to generate feature recognition algorithms for recognizing features from geometry, (b) to generate feature producing procedures to be used in design by feature approaches, and (c) to serve as a neutral feature data exchange medium between representations.

Research on Feature-Based Rapid Programming for Aircraft NC Parts

2007 ◽  
Vol 10-12 ◽  
pp. 682-687 ◽  
Author(s):  
Ying Guang Li ◽  
T.L. Fang ◽  
S.J. Cheng ◽  
W.H. Liao
Keyword(s):  
Feature Recognition ◽  
Tool Path ◽  
Data Transfer ◽  
Tool Path Generation ◽  
Path Generation ◽  
Transfer Standard ◽  
Manufacturing Enterprises ◽  
Nc Programming ◽  
Feature Based

Feature-based programming is one of tendency of NC programming technology, and it is also an important portion for CAD/CAPP/CAM integration in the manufacturing enterprises. Because of selecting geometry repeatedly, random programming and bad integration during programming for the aircraft NC parts, the technology of rapid programming based on features is put forward in this paper. On the basis of features, the technology of feature recognition for aircraft NC parts and the algorithm of tool path generation based on features are integrated by taking XML as data transfer standard. With this method, the programming for aircraft NC parts can be realized quickly in the condition of CAD/CAPP/CAM integration. The system developed has been well applied to the programming for aircraft NC parts in an aircraft corporation.

CAD Data Exhange and CAD Standards

2009 ◽  
pp. 32-53
Author(s):  
Xun Xu
Keyword(s):  
Data Exchange ◽  
Data Transfer ◽  
High Tech ◽  
Engineering Model ◽  
Data Interoperability ◽  
Cad System ◽  
Data Formats ◽  
Heavy Equipment ◽  
Feature Based ◽  
Original Equipment Manufacturers

Today, more companies than ever before are involved in manufacturing various parts of their end products using different subcontractors, many of whom are often geographically diverse. The rise of such global efforts has created the need for sharing information among vendors involved in multi-disciplinary projects. Transfer of data is necessary so that, for example, one organization can be developing a CAD model, while another performs analysis work on the same model; at the same time a third organization is responsible for manufacturing the product. Data transfer fills the need to satisfy each of these functions in a specific way. Accurate transmission is of paramount importance. Thus, a mechanism for good data transfer is needed. The CAD interoperability issue - using one CAD system in-house, yet needing to deliver designs to, or receive designs from, another system, poses a challenge to industries such as automotive, aerospace, shipbuilding, heavy equipment, and high-tech original equipment manufacturers and their suppliers. It is worth studying the issue and determining how engineering model data is delivered today to manufacturers and suppliers, how CAD conversion, geometric translation, and/or feature-based CAD interoperability are handled, at what expense, and under whose authority. This chapter explores the various ways to make this vital transfer possible. The attention will be directed towards data exchange and standards for 3-D CAD systems. Since CAD data formats have a lot to do with CAD kernels that govern the data structure and therefore the data formats, some popular CAD kernels are discussed. The data interoperability section covers different types of data translations and conversions. The use of neutral or standardized data exchange protocols is one of the natural methods for data exchange and sharing. This topic is covered at the end of this chapter.

Machining Feature-Based CAD/CAPP for STEP-NC

2014 ◽  
Vol 598 ◽  
pp. 591-594 ◽  
Author(s):  
Li Yan Zhang
Keyword(s):  
Process Planning ◽  
Manufacturing Process ◽  
Data Transfer ◽  
Operation Planning ◽  
Computer Aided Process Planning ◽  
Machining Feature ◽  
Computer Aided ◽  
Cad Cam ◽  
Feature Based ◽  
Cam Systems

ISO 14649, known as STEP-NC, is new model of data transfer between CAD/CAM systems and CNC machines. In this paper, the modeling based on machining feature is proposed. The machining feature comes from the manufacturing process considering the restriction of machining technology and machining resource. Then the framework for computer aided process planning is presented, where the algorithms of operation planning is studied. The practical example has been provided and results indicate that machining feature based model can integrate with CAPP and STEP-NC seamlessly.

Geometric Reasoning Based on Graph Grammar Parsing

1994 ◽  
Vol 116 (3) ◽  
pp. 763-769 ◽  
Author(s):  
Z. Fu ◽  
A. de Pennington
Keyword(s):  
Intelligent Design ◽  
Feature Recognition ◽  
Geometric Reasoning ◽  
Geometric Constraints ◽  
Graph Grammar ◽  
Feature Interaction ◽  
Knowledge Based ◽  
Feature Based ◽  
Feature Information ◽  
And Performance

It has been recognized that future intelligent design support environments need to reason about the geometry of products and to evaluate product functionality and performance against given constraints. A first step towards this goal is to provide a more robust information model which directly relates to design functionality or manufacturing characteristics, on which reasoning can be carried out. This has motivated research on feature-based modelling and reasoning. In this paper, an approach is presented to geometric reasoning based on graph grammar parsing. Our approach is presented to geometric reasoning based on graph grammar parsing. Our work combines methodologies from both design by features and feature recognition. A graph grammar is used to represent and manipulate features and geometric constraints. Geometric constraints are used within symbolical definitions of features constraints. Geometric constraints are used within symbolical definitions of features and also to define relative position and orientation of features. The graph grammar parsing is incorporated with knowledge-based inference to derive feature information and propagate constraints. This approach can be used for the transformation of feature information and to deal with feature interaction.

Approximate Degree Reduction of NURBS Curves and Surfaces: An Integrated Approach

1994 ◽  
Author(s):  
Srinivasa P. Varanasi ◽  
Athamaram H. Soni
Keyword(s):  
Shape Control ◽  
Data Exchange ◽  
Data Transfer ◽  
Integrated Approach ◽  
Free Form ◽  
Aircraft Industry ◽  
Trimmed Surfaces ◽  
Curves And Surfaces ◽  
High Degree ◽  
Boundary Curves

Abstract Data exchange between different CAD systems usually requires conversion between different representations of free-form curves and surfaces. Also, trimmed surfaces give rise to high degree boundary curves. Accurate conversion of these forms becomes necessary for reliable data transfer. Also important is the issue of shape control, specially in the aircraft industry. The objective of this paper is to investigate conversion methods and effect of shape control on the design and choice of such methods.

Feature-Based Machining Precedence Reasoning and Sequence Planning

1998 ◽  
Author(s):  
Yong Se Kim ◽  
Eric Wang ◽  
Choong Soo Lee ◽  
Hyung Min Rho
Keyword(s):  
Feature Recognition ◽  
Search Space ◽  
Machining Process ◽  
Planning System ◽  
Process Information ◽  
Computer Aided Process Planning ◽  
Sequence Planning ◽  
Precedence Relations ◽  
Feature Based ◽  
Form Features

Abstract This paper presents a feature-based method to support machining sequence planning. Precedence relations among machining operations are systematically generated based on geometric information, tolerance specifications, and machining expertise. The feature recognition method using Alternating Sum of Volumes With Partitioning (ASVP) Decomposition is applied to obtain a Form Feature Decomposition (FFD) of a part model. Form features are classified into a taxonomy of atomic machining features, to which machining process information has been associated. Geometry-based precedence relations between features are systematically generated using the face dependency information obtained by ASVP Decomposition and the features’ associated machining process information. Multiple sets of precedence relations are generated as alternative precedence trees, based on the feature types and machining process considerations. These precedence trees are further enhanced with precedence relations from tolerance specifications and machining expertise. Machining sequence planning is performed for each of these precedence trees, applying a matrix-based method to reduce the search space while minimizing the number of tool changes. The precedence trees may then be evaluated based on machining cost and other criteria. The precedence reasoning module and operation sequence planning module are currently being implemented within a comprehensive Computer-Aided Process Planning system.

JCAMP-DX for NMR

1993 ◽  
Vol 47 (8) ◽  
pp. 1093-1099 ◽  
Author(s):  
Antony N. Davies ◽  
Peter Lampen
Keyword(s):  
Spectral Data ◽  
Data Exchange ◽  
Data Transfer ◽  
Nmr Imaging ◽  
Successful Implementation ◽  
Independent Data ◽  
Imaging Data ◽  
Loss Of Information ◽  
Storage Media ◽  
Different Origin

Following the development and publication of the JCAMP-DX protocol 4.24 and its successful implementation in the field of infrared spectroscopy, data exchange without loss of information, between systems of different origin and internal format, has become a reality. The benefits of this system-independent data transfer standard have been recognized by workers in other areas who have expressed a wish for an equivalent, compatible standard in their own fields. This publication details a protocol for the exchange of Nuclear Magnetic Resonance (NMR) spectral data without any loss of information and in a format that is compatible with all storage media and computer systems. The protocol detailed below is designed for spectral data transfer, and its use for NMR imaging data transfer has not as yet been investigated.

scholarly journals Using Mobile Elements as Dynamic Bridges in Sparse Wireless Sensor Networks

2014 ◽  
pp. 107
Author(s):  
Hoang Dang Hai ◽  
Thorsten Strufe ◽  
Pham Thieu Nga ◽  
Hoang Hong Ngoc ◽  
Nguyen Anh Son ◽  
...  
Keyword(s):  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Data Exchange ◽  
Data Transfer ◽  
Mobile Elements ◽  
Sensor Nodes ◽  
Pollution Monitoring ◽  
Wireless Sensor ◽  
Mobile Nodes ◽  
Road Distance

Sparse  Wireless  Sensor  Networks  using several  mobile  nodes  and  a  small  number  of  static sensor  nodes  have  been  widely  used  for  many applications,  especially  for  traffic-generated  pollution monitoring.  This  paper  proposes  a  method  for  data collection and forwarding using Mobile Elements (MEs), which are moving on predefined trajectories in contrast to previous works that use a mixture of MEsand static nodes. In our method, MEscan be used as data collector as well as dynamic bridges for data transfer. We design the  trajectories  in  such  a  way,  that  they  completely cover  the  deployed  area  and  data  will  be  gradually forwarded  from  outermost  trajectories  to  the  center whenever  a  pair  of MEs contacts  each  other  on  an overlapping road distance of respective trajectories. The method  is based  on  direction-oriented  level  and  weight assignment.  We  analyze  the  contact  opportunity  for data  exchange  while MEs move.  The  method  has  been successfully tested for traffic pollution monitoring in an urban area.

scholarly journals Image Gradient-based Joint Direct Visual Odometry for Stereo Camera

2017 ◽  
Author(s):  
Jianke Zhu
Keyword(s):  
Visual Odometry ◽  
Research Problem ◽  
Feature Representation ◽  
Local Optimum ◽  
Multi Scale ◽  
Illumination Changes ◽  
Pyramid Scheme ◽  
Gradient Based ◽  
Feature Based ◽  
Dense 3D Reconstruction

Visual odometry is an important research problem for computer vision and robotics. In general, the feature-based visual odometry methods heavily rely on the accurate correspondences between local salient points, while the direct approaches could make full use of whole image and perform dense 3D reconstruction simultaneously. However, the direct visual odometry usually suffers from the drawback of getting stuck at local optimum especially with large displacement, which may lead to the inferior results. To tackle this critical problem, we propose a novel scheme for stereo odometry in this paper, which is able to improve the convergence with more accurate pose. The key of our approach is a dual Jacobian optimization that is fused into a multi-scale pyramid scheme. Moreover, we introduce a gradient-based feature representation, which enjoys the merit of being robust to illumination changes. Furthermore, a joint direct odometry approach is proposed to incorporate the information from the last frame and previous keyframes. We have conducted the experimental evaluation on the challenging KITTI odometry benchmark, whose promising results show that the proposed algorithm is very effective for stereo visual odometry.

Heuristics Based Feature Recognition: A Graph Approach

1994 ◽  
Author(s):  
Shyam V. Narayan ◽  
Zhi-Kui Ling
Keyword(s):  
Engineering Design ◽  
Surface Finish ◽  
Feature Recognition ◽  
Graph Representation ◽  
Heuristic Rules ◽  
Feature Identification ◽  
Design And Manufacturing ◽  
Feature Based ◽  
Manufacturing Features

Abstract Feature based modeling has been used as a means to bridge the gap between engineering design and manufacturing. Features can represent an artifact with higher level entities which relate directly to its design functionalities and manufacturing characteristics, such as surface finish, manufacturability, fits, tolerance etc. In this study, a heuristic based feature recognition approach is proposed by using the graph representation of a design. The process consists of two steps: subgraph construction, and subgraph to feature identification. In this study, the subgraph construction is accomplished by using a set of heuristic rules. The process of subgraph to feature identification is carried out with a set of integers and characters which represent the geometric, topological, and semantic characteristics of the corresponding feature. This feature recognition scheme is used for the identification of machine features in a design.

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