A Boundary-Blending Method for the Parametrization of 2D Surfaces With Highly Irregular Boundaries

2004 ◽  
Vol 126 (2) ◽  
pp. 327-335 ◽  
Author(s):  
Jui-Jen Chuang ◽  
Daniel C. H. Yang
Keyword(s):  
Dual Process ◽  
Fine Tuning ◽  
New Method ◽  
Laplace Method ◽  
Distribution Problem ◽  
Geometric Information ◽  
Geometric Properties ◽  
Blending Method ◽  
The Given ◽  
Boundary Curves

In this paper three methods are used to generate boundary-conformed parametrization of 2D surfaces. They include two conventional approaches, the Coons method and the Laplace method, and a new method, called “boundary-blending method.” In this new method, unidirectional 2D parametrization is achieved based on the geometric information of the given boundary curves. A dual offsetting procedure is adopted. The geometric properties considered for offsettings include position, curvature, and normal of the two facing parent curves. The algorithm contains two adjustable parameters that enable fine-tuning of this parametrization. This unidirectional process can be easily extended to bi-directional parametrization via superposition to include both boundary pairs. Examples show that this algorithm leads to reasonable smooth blending of the boundaries, and the dual process achieves seamless converging at the middle. It is more robust than the Coons method with regard to parametrization anomalies and relieves the relatively large uneven grid distribution problem experienced in the Laplace method. We believe that this method provides a useful alternative for the 2D boundary-conformed parametrization problems.

Constrained Shape Scaling of Trimmed NURBS Surfaces

1999 ◽  
Author(s):  
Pifu Zhang ◽  
Caiming Zhang ◽  
Fuhua (Frank) Cheng
Keyword(s):  
Data Exchange ◽  
Surface Deformation ◽  
Current Data ◽  
Free Form ◽  
Test Results ◽  
Nurbs Surface ◽  
Curvature Distribution ◽  
The Given ◽  
Boundary Curves

Abstract A method to scale and deform a trimmed NURBS surface while holding the shape and size of specific features (trimming curves) unchanged is presented. The new surface is formed by scaling the given surface according to the scaling requirement first; and then attaching the (original) features to the scaled NURBS surface at appropriate locations. The attaching process requires several geometric operations and constrained free-form surface deformation. The resulting surface has the same features as the original surface and same boundary curves as the scaled surface while reflecting the shape and curvature distribution of the scaled surface. This is achieved by minimizing a shape-preserving objective function which covers all the factors in the deformation process such as bending, stretching and spring effects. The resulting surface maintains a NURBS representation and, hence, is compatible with most of the current data-exchange standards. Test results on several car parts with trimming curves are included. The, quality of the resulting surfaces is examined using the highlight line model.

Oxygen as single oxidant for two steps: base-free one-pot Pd(ii)-catalyzed alcohol oxidation & arylation to halogen-intact β-aryl α,β-enones

RSC Advances ◽  
2014 ◽  
Vol 4 (85) ◽  
pp. 45490-45494 ◽  
Author(s):  
Mari Vellakkaran ◽  
Murugaiah M. S. Andappan ◽  
Kommu Nagaiah
Keyword(s):  
Allyl Alcohol ◽  
Alcohol Oxidation ◽  
Fine Tuning ◽  
New Method ◽  
One Pot ◽  
Arylboronic Acids ◽  
Catalyzed Oxidation

Using oxygen as the sole oxidant for two steps, we developed a new method to synthesize β-aryl α,β-enones by fine-tuning the Pd(ii)-catalyzed oxidation of allyl alcohol to subsequent arylation with arylboronic acids, arylboronic ester and aryltrifluoroborate salt.

Research on Cutter’s Position and Pose for Chamfering Spiral Bevel Gear Addendum

2010 ◽  
Vol 26-28 ◽  
pp. 976-981
Author(s):  
Xiu Ting Wei ◽  
Jing Cheng Liu ◽  
Qiang Du
Keyword(s):  
Tilt Angle ◽  
Bevel Gear ◽  
New Method ◽  
Spiral Bevel Gear ◽  
Tangent Circle ◽  
Center Position ◽  
Spiral Bevel ◽  
Boundary Curves

The cutter’s position and pose are key elements for chamfering addendum automatically and a new method for calculating the cutter’s position and pose is as follows: 1) Finding the chamfering boundary curves of addendum by offsetting the two top curves (convex and concave) of spiral bevel gear addendum respectively; 2) Dispersing the chamfering boundary curves; 3) Calculating the center position of the tangent circle along the chamfering boundary curves and taking this as the cutter’s center; 4) solving the tilt angle through the center position and the dispersed points on boundary curves. The proposed method lays foundation for chamfering automation.

scholarly journals An algorithm for estimating surface normal from its boundary curves

2014 ◽  
Vol 2 (1) ◽  
pp. 67-72 ◽  
Author(s):  
Jisoon Park ◽  
Taewon Kim ◽  
Seung-Yeob Baek ◽  
Kunwoo Lee
Keyword(s):  
Surface Model ◽  
Geometric Information ◽  
User Intent ◽  
Geometry Modeling ◽  
Modeling Process ◽  
New Information ◽  
Normal Vectors ◽  
The One ◽  
Boundary Curves ◽  
Curve Networks

Abstract Recently, along with the improvements of geometry modeling methods using sketch-based interface, there have been a lot of developments in research about generating surface model from 3D curves. However, surfacing a 3D curve network remains an ambiguous problem due to the lack of geometric information. In this paper, we propose a new algorithm for estimating the normal vectors of the 3D curves which accord closely with user intent. Bending energy is defined by utilizing RMF(Rotation-Minimizing Frame) of 3D curve, and we estimated this minimal energy frame as the one that accords design intent. The proposed algorithm is demonstrated with surface model creation of various curve networks. The algorithm of estimating geometric information in 3D curves which is proposed in this paper can be utilized to extract new information in the sketch-based modeling process. Also, a new framework of 3D modeling can be expected through the fusion between curve network and surface creating algorithm.

scholarly journals A New Method for Inextensible Flows of Timelike Curves in Minkowski Space-Time E14

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Talat Körpinar
Keyword(s):  
Partial Differential Equations ◽  
Differential Equations ◽  
Minkowski Space ◽  
Space Time ◽  
New Method ◽  
Frenet Frame ◽  
Partial Differential ◽  
Minkowski Space Time ◽  
Inextensible Flows ◽  
The Given

We construct a new method for inextensible flows of timelike curves in Minkowski space-time E14. Using the Frenet frame of the given curve, we present partial differential equations. We give some characterizations for curvatures of a timelike curve in Minkowski space-time E14.

A new method of precise orientation adjustment based on matrix similarity for large-scale component

2018 ◽  
Vol 38 (2) ◽  
pp. 207-215 ◽  
Author(s):  
Dian Wu ◽  
Fuzhou Du
Keyword(s):  
Large Scale ◽  
Fine Tuning ◽  
New Method ◽  
Similarity Relation ◽  
Adjustment Process ◽  
Content Type ◽  
Mapping Model ◽  
Orientation Deviation ◽  
Actual Operation ◽  
Matrix Similarity

Purpose In the assembly process of the satellite, there will be multiple installation and disassembly operations for the solar wing and the main satellite body (or simulator). However, the traditional method of orientation adjustment by theodolite and two-axis turntable is difficult to coordinate three rotation angles of yaw, pitch and roll, which leads to the complexity of actual operation and dependency on manual experience. Therefore, this paper aims to propose a new method to achieve rapid and precise orientation adjustment. Design/methodology/approach The similarity relation of the orientation variation matrix in a different coordinate system is studied, and a mapping model of the similarity relation is established. By using multiple element matrices to construct the original rotation matrix, the mapping is solved in quaternion form. Taking the theodolite as a measuring instrument and the Stewart platform as a control equipment, an experiment on installing the solar wing is performed to validate the effectiveness of the algorithm. Findings Based on the solving algorithm, the orientation adjustment process is simplified to a three-step fixed mode, which is three adjustments to get the parameter of the mapping model, one to adjust the component in place and another to further fine tuning. The final orientation deviation is less than 0.003° and close to the level of using a laser tracker, achieving the required accuracy of 0.0115°. Originality/value This paper reveals the similarity relation of the variation matrix in the process of orientation adjustment and presents a new method to achieve rapid and precise orientation adjustment for the large-scale component.

Complete Force Balancing of Spatial Linkages

1971 ◽  
Vol 93 (2) ◽  
pp. 620-626 ◽  
Author(s):  
Roger E. Kaufman ◽  
George N. Sandor
Keyword(s):  
Center Of Mass ◽  
Time Dependent ◽  
New Method ◽  
Operator Equations ◽  
Spatial Linkages ◽  
The Given

A new method permits the complete force balancing of spatial linkages such as the RSSR and RSSP mechanisms. Operator equations are written describing the location of the center of mass for the given mechanism. The coefficients of the time-dependent terms are set to zero by properly locating the mass centers of selected links. As a result, the location of the total center of mass is invariant and there is no resultant shaking force.

scholarly journals Intersect a quartic to extract its roots

2017 ◽  
Vol 16 (1) ◽  
pp. 73-76
Author(s):  
Raghavendra G. Kulkarni
Keyword(s):  
Quadratic Polynomial ◽  
New Method ◽  
Quadratic Equations ◽  
Quartic Polynomial ◽  
Root Term ◽  
The Given

AbstractIn this note we present a new method for determining the roots of a quartic polynomial, wherein the curve of the given quartic polynomial is intersected by the curve of a quadratic polynomial (which has two unknown coefficients) at its root point; so the root satisfies both the quartic and the quadratic equations. Elimination of the root term from the two equations leads to an expression in the two unknowns of quadratic polynomial. In addition, we introduce another expression in one unknown, which leads to determination of the two unknowns and subsequently the roots of quartic polynomial.

scholarly journals Pharmacovigilance with Transformers: A Framework to Detect Adverse Drug Reactions Using BERT Fine-Tuned with FARM

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Sajid Hussain ◽  
Hammad Afzal ◽  
Ramsha Saeed ◽  
Naima Iltaf ◽  
Mir Yasir Umair
Keyword(s):  
Adverse Drug Reactions ◽  
Text Classification ◽  
Pharmacological Action ◽  
Fine Tuning ◽  
Testing Time ◽  
Drug Reactions ◽  
Training Time ◽  
Proposed Model ◽  
End To End ◽  
The Given

Adverse drug reactions (ADRs) are the undesirable effects associated with the use of a drug due to some pharmacological action of the drug. During the last few years, social media has become a popular platform where people discuss their health problems and, therefore, has become a popular source to share information related to ADR in the natural language. This paper presents an end-to-end system for modelling ADR detection from the given text by fine-tuning BERT with a highly modular Framework for Adapting Representation Models (FARM). BERT overcame the predominant neural networks bringing remarkable performance gains. However, training BERT is a computationally expensive task which limits its usage for production environments and makes it difficult to determine the most important hyperparameters for the downstream task. Furthermore, developing an end-to-end ADR extraction system comprising two downstream tasks, i.e., text classification for filtering text containing ADRs and extracting ADR mentions from the classified text, is also challenging. The framework used in this work, FARM-BERT, provides support for multitask learning by combining multiple prediction heads which makes training of the end-to-end systems easier and computationally faster. In the proposed model, one prediction head is used for text classification and the other is used for ADR sequence labeling. Experiments are performed on Twitter, PubMed, TwiMed-Twitter, and TwiMed-PubMed datasets. The proposed model is compared with the baseline models and state-of-the-art techniques, and it is shown that it yields better results for the given task with the F -scores of 89.6%, 97.6%, 84.9%, and 95.9% on Twitter, PubMed, TwiMed-Twitter, and TwiMed-PubMed datasets, respectively. Moreover, training time and testing time of the proposed model are compared with BERT’s, and it is shown that the proposed model is computationally faster than BERT.

scholarly journals Dynamic Time Slice Calculation for Round Robin Process Scheduling Using NOC

2015 ◽  
Vol 5 (6) ◽  
pp. 1480
Author(s):  
G Siva Nageswara Rao ◽  
N. Srinivasu ◽  
S.V.N. Srinivasu ◽  
G. Rama Koteswara Rao
Keyword(s):  
Scheduling Algorithm ◽  
Turnaround Time ◽  
Round Robin ◽  
Fine Tuning ◽  
New Method ◽  
Time Slice ◽  
Process Scheduling ◽  
Time Duration ◽  
Dynamic Time ◽  
Ready Queue

<p>Process scheduling means allocating a certain amount of CPU time to each of the user processes.  One of the popular scheduling algorithms is the “Round Robin” algorithm, which allows each and every process to utilize the CPU for short time duration.  Processes which finish executing during the time slice are removed from the ready queue.  Processes which do not complete execution during the specified time slice are removed from the front of the queue, and placed at the rear end of the queue. This paper presents an improvisation to the traditional round robin scheduling algorithm, by proposing a new method. The new method represents the time slice as a function of the burst time of the waiting process in the ready queue. Fixing the time slice for a process is a crucial factor, because it subsequently influences many performance parameters like turnaround time, waiting time, response time and the frequency of context switches.  Though the time slot is fixed for each process, this paper explores the fine-tuning of the time slice for processes which do not complete in the stipulated time allotted to them.</p>

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