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.

Geometric Reasoning Based on Graph Grammar Parsing

1991 ◽  
Author(s):  
Zhuo Fu ◽  
Alan de Pennington
Keyword(s):  
Intelligent Design ◽  
Feature Recognition ◽  
Geometric Reasoning ◽  
Geometric Constraints ◽  
Graph Grammar ◽  
Feature Interaction ◽  
Knowledge Based ◽  
Feature Based ◽  
Feature Information ◽  
And Performance

Abstract It has been recognized that future intelligent design support environments need to be able 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 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 symbolic definitions of features and also to define relative position and orientation of features. The graph grammar parsing is incorporated with knowledge-based techniques to derive feature information and propagate constraints. This approach can be used to the transformation of feature information and to deal with feature interaction.

Unified Feature Definition for Feature Based Design and Feature Based Manufacturing

1995 ◽  
Author(s):  
Reinholt Geelink ◽  
Otto W. Salomons ◽  
Fjodor van Slooten ◽  
Fred J. A. M. van Houten ◽  
Huub J. J. Kals
Keyword(s):  
Feature Recognition ◽  
Design Feature ◽  
Geometric Constraints ◽  
Planning System ◽  
Conceptual Graphs ◽  
Computer Aided Process Planning ◽  
Feature Based ◽  
Definition Of ◽  
Feature Based Design ◽  
Interactive Feature

Abstract In this paper, interactive “constraint based feature definition” is used to drive both feature based design and feature recognition. At present, hardly any feature based CAD or CAPP system does offer adequate facilities to easily define application specific features. Feature definition by means of programming is an error prone and difficult task. The definition of new features has to be performed by domain experts in the fields of design and manufacturing. In general they will not be programming experts. This paper elaborates on interactive feature definition, aiming at facilitating the definition of features by non-programming experts. The interactive feature definition functionality is implemented in a re-design support system called FROOM. It supports feature based design. Feature definition is also used in a Computer Aided Process Planning system, called PART, for the definition of features to be recognized. Conceptual graphs are used as an aid in the definition of features and for the representation of the features. The conceptual graphs are automatically transformed into feature recognition algorithms. Degrees of freedom (DOF) analysis is used for support during feature definition and for solving geometric constraints related to the feature to be defined.

An Integrated DFM System for Milling

1997 ◽  
Author(s):  
Subramanian Krishnan ◽  
Edward B. Magrab
Keyword(s):  
Feature Recognition ◽  
Integrated Design ◽  
Geometric Reasoning ◽  
New Approach ◽  
Design For Manufacture ◽  
Minimum Number ◽  
Feature Based ◽  
Two Stages ◽  
Manufacturability Evaluation ◽  
General Profile

Abstract An integrated design for manufacture system for milling is developed by introducing a fundamental manufacturing entity for milling (FMEM), which represents a volume to be machined. A part is created by subtracting a user created set of FMEMs from a rectangular prismatic stock. Manufacturability evaluation is done in two stages: (1) after creating each FMEM; and (2) after placing and subtracting the volume from the stock. It is shown that the commonly used 2½ -D features used to mill a part such as slots, pockets and holes are a subset of the FMEM. Furthermore, all specific shapes of the general FMEM are represented by one compact data structure. It is demonstrated that using process specific entities greatly simplifies manufacturability evaluation, which makes it possible to base the geometric reasoning algorithms on the entity’s most general profile rather than on only a set of specific shapes. A new approach using the FMEMs is presented for generating an integrated process and fixture plan with a minimum number of setup and tool changes. The advantages of using the process specific entities approach for design and manufacturability analysis over the feature recognition approach and feature based approach are enumerated.

A Framework for Feature Based Part Modeling

1991 ◽  
Author(s):  
Yuh-Min Chen ◽  
R. Allen Miller ◽  
K. Rao Vemuri
Keyword(s):  
Geometric Reasoning ◽  
Geometric Information ◽  
Cad System ◽  
Knowledge Based ◽  
Modeling Environment ◽  
Cad Cam ◽  
Feature Based ◽  
High Level ◽  
Feature Based Design ◽  
Part Modeling

Abstract To increase the capabilities and intelligence of CAD/CAM systems, a feature based modeling environment, integrated with a knowledge based environment, is under development utilizing a commercial CAD system. This environment allows designers to model parts with features, and provides high-level part models to support geometric reasoning in manufacturing assessment and related functions. Two fundamental issues have been considered: (1) What kind of information is required to specify a part and to support reasoning about the part in a wide variety of applications?, and (2) How can the results serve the geometric reasoning needs of the various engineering applications which need geometric information about the part? This paper will discuss the information required for defining net shaped parts (parts to be manufactured by net shape processes), a framework for a feature based modeling environment, the procedures for feature based design, and the construction of high-level (semantic) pan models suitable for geometric reasoning in a knowledge based environment.

Feature Interactions

2009 ◽  
pp. 109-125
Author(s):  
Xun Xu
Keyword(s):  
Feature Recognition ◽  
Basic Feature ◽  
Feature Model ◽  
Design System ◽  
Feature Interaction ◽  
Complete Suppression ◽  
Feature Interactions ◽  
Feature Based ◽  
The One ◽  
Feature Based Design

Feature interaction tends to have a wide range of consequences and effects on a feature model and its applications. While these may often be intended, it is also true that feature validity can be violated, one way or another, by feature interactions (Shah & Mäntylä, 1995, Gao & Shah, 1998, Lee & Kim, 1998). They may affect the semantics of a feature, ranging from slight changes in actual parameter values, to some substantial alterations to both geometry and topology or even complete suppression of its contribution to the model shape. To certain extent, successful applications of feature recognition and feature-based techniques have been hindered by interactions among the features. Feature interaction was first studied in relation to feature recognition systems. As an alternative to feature recognition, feature-based design methodology has also become prevalent in recent years. Although a number of successful and commercially available feature-based design systems have been reported, current CAD technology is still unable to provide an effective solution for fully handling the complexity of feature interactions. Very often in a feature-based design system, the interaction between two features gives rise to an unintended feature, nullifying the one-to-one mapping from design features to manufacturing features. The resulting manufacturing feature is usually of a form that the system cannot handle or represent. Thus feature interaction resolution is equally essential for a feature-based design system (Dereli & Baykasoglu, 2004). As discussed in Chapter IV, features can be represented either as a set of faces or as a volume. The interactions between surface features are different from those occurring between volumetric features. This chapter discusses different types of interactions that arise from these two feature representation schemes and uses the interacting entities to classify them. There are two types of surface feature interactions, basic feature interaction and complex feature interaction. Three types of basic feature interactions are discussed. They are nested, overlapping, and intersecting types. Interacting patches are used to classify volumetric feature interactions. These interacting patches can be of a containing, contained, or overlapping type. The significance of feature interactions lies in their effect on the machining sequence of the features involved. This is also discussed in this chapter. When features are close to each other but do not share any geometric entities, interactions may also happen for structural reasons. This type of feature interaction can be called interaction by vicinity. The main aim of this chapter is to take a holistic approach toward feature interaction solutions. The example parts used are from the “Catalogue of the NIST (National Institute of Standards and Technology) Design, Planning and Assembly Repository” (Regli & Gaines, 1996). A case study is provided in the end of the chapter.

The Contingent Effect of Team Composition on the Performance of Entrepreneurial Teams

2019 ◽  
pp. 654-680
Author(s):  
Serghei Musaji ◽  
Julio De Castro
Keyword(s):  
Future Research ◽  
Team Composition ◽  
Team Members ◽  
Team Diversity ◽  
Entrepreneurial Teams ◽  
Knowledge Based ◽  
Fertile Ground ◽  
Active Debate ◽  
And Performance ◽  
The Relationship

Despite the continuous interest in studying entrepreneurial teams, the relationship between team composition and, particularly, team diversity and performance remains fertile ground for active debate. Taking roots in the knowledge-based view and organizational learning literatures, this chapter argues that performance in entrepreneurial teams is contingent on (a) the overlap between team members’ knowledge/competences and the content of the performed tasks, (b) the duplication of the team members’ knowledge in the areas with that content, (c) the nature of tasks (exploration or exploitation), (d) the team’s flexibility to adapt to changes in the content and nature of those tasks, and (e) the rate of environmental change. Because an important source of ambiguity in the understanding of how team diversity and performance are linked ties to issues of how team diversity is conceptualized and operationalized, the chapter also proposes a new way of looking at diversity in future research.

scholarly journals Microcontroller Based Flexible Modulation Scheme of MLI Operation for Selective Lower Levels: A Knowledge Based Approach

2016 ◽  
Vol 2016 ◽  
pp. 1-11
Author(s):  
R. K. Dhatrak ◽  
R. K. Nema ◽  
D. M. Deshpande
Keyword(s):  
Pulse Generation ◽  
Multilevel Inverter ◽  
Experimental Results ◽  
Modulation Scheme ◽  
Inductive Load ◽  
Medium Voltage ◽  
Knowledge Based ◽  
Common Mode Voltage ◽  
Power Modules ◽  
And Performance

In today’s industrial world multilevel inverter (MLI) got a significant importance in medium voltage application and also a very potential topic for researchers. It is experienced that studying and comparing results of multilevel inverter (MLI) at distinct levels are a costlier and time consuming issue for any researcher if he fabricate different inverters for each level, as designing power modules simultaneously for different level is a cumbersome task. In this paper a flexible quotient has been proposed to recognize possible conversion of available MLI to few lower level inverters by appropriately changing microcontroller programming. This is an attempt to obtain such change in levels through simulation using MATLAB Simulink on inductive load which may also be applied to induction motor. Experimental results of pulse generation using dsPIC33EP256MC202 demonstrate the feasibility of proposed scheme. Proposed flexible quotient successfully demonstrates that a five-level inverter may be operated as three and two levels also. The paper focuses on odd levels only as common mode voltage (CMV) can be reduced to zero and performance of drives is better than even level. Simulated and experimental results are given in paper.

Automatic Parametric Modeling From Non-Feature Based Designs for Additive Manufacturing

2021 ◽  
Author(s):  
Xinyi Xiao ◽  
Byeong-Min Roh
Keyword(s):  
Additive Manufacturing ◽  
3D Models ◽  
Parametric Modeling ◽  
Parametric Models ◽  
Performance Simulation ◽  
Cad Modeling ◽  
3D Cad ◽  
Feature Based ◽  
And Performance ◽  
The Given

Abstract The integration of Topology optimization (TO) and Generative Design (GD) with additive manufacturing (AM) is becoming advent methods to lightweight parts while maintaining performance under the same loading conditions. However, these models from TO or GD are not in a form that they can be easily edited in a 3D CAD modeling system. These geometries are generally in a form with no surface/plane information, thus having non-editable features. Direct fabricate these non-feature-based designs and their inherent characteristics would lead to non-desired part qualities in terms of shape, GD&T, and mechanical properties. Current commercial software always requires a significant amount of manual work by experienced CAD users to generate a feature-based CAD model from non-feature-based designs for AM and performance simulation. This paper presents fully automated shaping algorithms for building parametric feature-based 3D models from non-feature-based designs for AM. Starting from automatically decomposing the given geometry into “formable” volumes, which is defined as a sweeping feature in the CAD modeling system, each decomposed volume will be described with 2D profiles and sweeping directions for modeling. The Boolean of modeled components will be the final parametric shape. The volumetric difference between the final parametric form and the original geometry is also provided to prove the effectiveness and efficiency of this automatic shaping methodology. Besides, the performance of the parametric models is being simulated to testify the functionality.

Capturing and Using Designer Intent in a Design-With-Features System

1991 ◽  
Author(s):  
Eric H. Nielsen ◽  
John R. Dixon ◽  
George E. Zinsmeister
Keyword(s):  
Computer Aided Design ◽  
Simultaneous Equation ◽  
The Core ◽  
Knowledge Based ◽  
Evaluation Procedures ◽  
Equation Solving ◽  
Feature Based ◽  
Design Systems ◽  
Aided Design ◽  
Intelligent Computer

Abstract The goal of “intelligent” computer-aided-design (CAD) systems is to provide greater support for the process of design, as distinguished from drafting and analysis. More supportive design systems should provide a quick and simple means of creating and modifying design configurations, automating evaluation procedures (e.g., for manufacturing), and automating interfaces to analysis procedures. In this paper we are concerned with the issues of representing in-progress designs so that such goals can be met. A feature-based representation is proposed in which features are defined as possessing not only form but also certain designer intentions regarding geometric relationships. A working experimental version of a design-with-features system using this representation for thin-walled components illustrates its use in composing a design as a configuration of feature-forms, in modifying the design geometry through automatic, intelligent incorporation and propagation of designer-initiated geometry changes, and in providing for the generation of user-defined features. In contrast to constraint-driven simultaneous equation solving methods, this system uses an intent-driven knowledge-based method to propagate and incorporate geometry modifications not only in fully-constrained designs, but also in over- and under-constrained designs. Issues of manageability, extensibility, and computationally efficiency were considered in the development of the core services of the system.

An Interactive Graphical Approach to Feature Modeling Using Halfspaces and Geometric Constraints

1990 ◽  
Author(s):  
Maarten J. G. M. van Emmerik
Keyword(s):  
Spatial Relations ◽  
Feature Modeling ◽  
Geometric Constraints ◽  
Boolean Combination ◽  
Graphical Approach ◽  
Geometric Characteristics ◽  
Feature Based ◽  
New Feature ◽  
High Level ◽  
And Control

Abstract Feature modeling enables the specification of a model with standardized high-level shape aspects that have a functional meaning for design or manufacturing. In this paper an interactive graphical approach to feature-based modeling is presented. The user can represent features as new CSG primitives, specified as a Boolean combination of halfspaces. Constraints between halfspaces specify the geometric characteristics of a feature and control feature validity. Once a new feature is defined and stored in a library, it can be used in other objects and positioned, oriented and dimensioned by direct manipulation with a graphics cursor. Constraints between features prevent feature interference and specify spatial relations between features.

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