General Form Tolerance Evaluation Using Non-Uniform Rational B-Splines

1996 ◽  
Author(s):  
Hong-Tzong Yau ◽  
Kuei-Wu Chen
Keyword(s):  
Measurement Data ◽  
Cad Model ◽  
Turbine Wheel ◽  
B Splines ◽  
Model Based ◽  
Form Tolerance ◽  
Modern Manufacturing ◽  
The Subject ◽  
Form Features ◽  
Best Fit

Abstract Tolerance evaluation is critical to quality assurance in modern manufacturing. In contrast to traditional measurement which relies on specific hard gauges, coordinate measuring machines provide more flexibility for dimensional measurement and tolerance evaluations. To fully automate CMM inspection and tolerance evaluation, CAD/CMM integration is an important key. Although the subject of CAD-directed inspection has been widely researched, CAD model-based tolerance evaluation has received less attention. This paper presents a CAD model-based approach for evaluating general form tolerances using non-uniform rational B-splines. Unlike classical methods which construct substitute geometric features from the measurement data, this method evaluates form tolerances by comparing the measurement data with a nominal CAD model. Nonuniform rational B-splines (NURBS) is used to represent general form features since NURBS offers a common format for modeling precisely all the different form features. With this unified database, a general best-fit algorithm is developed that can be applied to the evaluation of various form tolerances. Computer simulations have been performed on different form features to study the robustness and efficiency of the algorithm. Application to the measurement of turbine wheel die segment is also presented.

CAD Model-Based Localization of Parts in Manufacturing

Computer ◽  
1987 ◽  
Vol 20 (8) ◽  
pp. 66-74 ◽  
Author(s):  
Gunnarsson ◽  
Prinz
Keyword(s):  
Cad Model ◽  
Model Based

scholarly journals Application of Model-Based Tests for Analysing the Consequences of Mine Fires

2018 ◽  
Vol 1 (1) ◽  
pp. 767-774
Author(s):  
Magdalena Tutak
Keyword(s):  
Fire Hazard ◽  
Physical Parameters ◽  
Gas Mixture ◽  
New Approach ◽  
Model Based ◽  
Underground Coal Mines ◽  
Mine Fires ◽  
Underground Mine Workings ◽  
The Subject ◽  
Chemical Products

Abstract One of the most common and most dangerous hazards in underground coal mines is fire hazard. Mine fires can be exogenous or endogenous in nature. In the case of the former, a particular hazard is posed by methane fires that occur in dog headings and longwalls. Endogenous and exogenous fires are large hazard for working crew in mining headings and cause economics losses for mining plants. Mine fires result in emission of harmful chemical products and have a crucial impact on the physical parameters of the airflow. The subject of the article concerns the analysis of the consequences of methane fires in dog headings. These consequences were identified by means of model-based tests. For this purpose, a model was developed and boundary conditions were adopted to reflect the actual layout of the headings and the condition of the atmosphere in the area under analysis. The objective of the test was to determine the effects of methane fires on the chemical composition of the atmosphere and the physical parameters of the gas mixture generated in the process. The results obtained clearly indicate that fires have a significant impact on the above-mentioned values. The paper presents the distributions for the physical parameters of the resulting gas mixture and the concentration of fire gases. Moreover, it shows the distributions of temperature and oxygen concentration levels in the headings under analysis. The methodology developed for the application of model-based tests to analyse fire events in mine headings represents a new approach to the problem of investigating the consequences of such fires. It is also suitable for variant analyses of the processes related to the ventilation of underground mine workings as well as for analyses of emergency states. Model-based tests should support the assessment of the methane hazard levels and, subsequently, lead to an improvement of work safety in mines.

scholarly journals Pembelajaran Mandri Berbasis Video 3GP

2018 ◽  
Vol 16 (2) ◽  
pp. 135-148
Author(s):  
Barnawi Barnawi
Keyword(s):  
Data Analysis ◽  
Learning Model ◽  
Research Field ◽  
Video Data ◽  
Effective Learning ◽  
Model Based ◽  
Research Population ◽  
The Subject ◽  
Simulation Learning ◽  
Self Learning

Abstract: Potency of the high absorption obtained if learning in effective. Effective learning occurs when students are placed as individual active and direct contact with the subject matter. This research aims to reduce the limitations of the tool (a computer or laptop) and maximizing existing facilities (hand phone) with the aim of achieving effective learning that puts students as subjects of learning. This study is a research field for conducting comparative academic performance of two models of learning. The first learning model is simulation learning and the second model is self-learning via mobile facility. Self-learning materials in this research is the material in the form of video 3GP and transferred to the student’s mobile. The research population is 85 students and a sample taken by 70 students. The data in this study is the performance of students from simulation learning model and self- learning model based 3GP video. Data analysis using inferential statistical, namely the t-test. Data analysis was performed after the fulfillment of the requirements for normality of data. The results of hypothesis testing obtained the results as following: The value t count bigger than t table (5.957> 2.025). Thus Ha is received and Ho is rejected (significance below or equal to 0.05 so Ha is received). Means that there are significant differences between simulation learning model and self-learning model based 3GP video. Keywords: Learning Media, 3GP Video.

Study of Donor Centres in n-InSb due to the Temperature Annealing

2005 ◽  
Vol 480-481 ◽  
pp. 197-200
Author(s):  
Y. Sayad ◽  
A. Nouiri
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Annealing Time ◽  
Annealing Temperature ◽  
Theoretical Study ◽  
Donor Concentration ◽  
Model Based ◽  
Proposed Model ◽  
Kinetics Of ◽  
Best Fit

An increasing of donor centres has been detected in n-InSb when it was submitted to anneal/quench with various annealing temperature (450 °C - 850 °C) and various annealing time (5 - 100 hours). A theoretical study of the kinetics of the conduction conversion of n-InSb at temperature annealing above 250 °C has been made. The present analysis indicates that the donor concentration increases with increasing of annealing time. In order to study this variation and to give a model for donor centres generated, a proposed model based on the simple kinetic is used to fit the variation of donor concentration as a function of annealing time. However, from the best fit of experimental data using the proposed model, the activation energy is determined.

Geometric Reasoning for the Coding of CAD Models

1995 ◽  
Author(s):  
A. Z. Qamhiyah ◽  
B. Benhabib ◽  
R. D. Venter
Keyword(s):  
Computer Aided Design ◽  
Feature Recognition ◽  
Effective Means ◽  
Boundary Representation ◽  
Cad Model ◽  
Cad System ◽  
Cad Models ◽  
Form Features ◽  
Feature Based Design ◽  
Design Retrieval

Abstract Many of today’s concurrent product-development cycles depend on the utilization of intelligent Computer-Aided Design (CAD) systems. Thus, it would be essential to provide CAD users with effective means for interacting with the CAD system and its database. This paper addresses the development of a boundary-based coding procedure for CAD models. Coding the geometric and processing characteristics of objects, based on their CAD model representation, has been long recognized as an effective approach that allows convenient design retrieval on the one hand and process-planning automation on the other. Our work is based on the assumption that form features are recognizable and extractable from the CAD model by current feature-recognition, feature extraction and feature-based-design approaches. The coding procedure is applicable to the boundary representation of the object and its extracted form features.

CAD Model Based System for Visual Inspection

1993 ◽  
pp. 669-674
Author(s):  
Jharna Majumdar ◽  
Krishnan Rangarajan ◽  
Adil Hameed
Keyword(s):  
Visual Inspection ◽  
Cad Model ◽  
Model Based

Comparison inspection between ICT images & CAD model based on edge extracting by neural networks

2011 ◽  
Vol 19 (10) ◽  
pp. 2533-2540
Author(s):  
曾理 ZENG Li ◽  
何洪举 HE Hong-ju ◽  
张志波 ZHANG Zhi-bo
Keyword(s):  
Neural Networks ◽  
Cad Model ◽  
Model Based
Sign in / Sign up

Export Citation Format

Share Document