Application of Regression Spline to Reverse Modeling

2006 ◽  
Vol 7 (1) ◽  
pp. 95-101 ◽  
Author(s):  
Giovanni Moroni ◽  
Marco Rasella
Keyword(s):  
Regression Analysis ◽  
Free Form ◽  
Statistical Regression ◽  
Flexible Approach ◽  
Point Sampling ◽  
Regression Spline ◽  
Curves And Surfaces ◽  
Modeling Environment ◽  
Systematic Behavior ◽  
Form Reconstruction

When dealing with inspection or reverse modeling, the problem of free-form curves and surfaces reconstruction has to be faced starting from a set of measured points. Because in point sampling the acquisition error is unavoidable, curves and surfaces fitting should be based on a rigorous diagnostic phase. We consider statistical regression analysis in which, treating error as a variable of the problem, we distinguish between the systematic behavior of measured points and noise in the reconstruction of curves and surfaces. The model we introduce for a regression based free-form reconstruction is the so-called regression spline. It is a well known model in the literature, with a consolidated theory and applications in fields such as chemical, econometric, and biomedical. Our purpose is to discuss the application of this powerful and flexible approach in a reverse modeling environment.

Freeform Shape Reconstruction Using Parametric Regression Spline

2008 ◽  
Author(s):  
Giovanni Moroni ◽  
Marco Rasella
Keyword(s):  
Shape Reconstruction ◽  
Free Form ◽  
Large Set ◽  
Statistical Regression ◽  
Closed Curves ◽  
Reconstruction Process ◽  
Shape Fitting ◽  
Regression Spline ◽  
Systematic Behavior ◽  
Frequency Behavior

In inspection or reverse engineering, free-form shapes are reconstructed from a large set of sampled points. Since point acquisition error is unavoidable, shape fitting should be based on a rigorous diagnostic phase. In this paper, a new parametrical form of regression spline is introduced. The method applies statistical regression analysis, with the error treated as a variable of the problem. Hence, during the reconstruction process we distinguish between the systematic behavior of the sampled points, which represents the part shape, and the hi-frequency behavior of noise. This distinction leads to realistic and efficient reconstruction of complex parts. Both the multi-valued and the closed curves and surfaces of smooth and non-homogeneous types are represented. This work presents the method and demonstrates its feasibility on freeform parts applied to a new parametrical form of regression spline.

Stress Analysis of Cement Concrete Pavement under Overweight Loads

2012 ◽  
Vol 446-449 ◽  
pp. 949-953
Author(s):  
Ya Ni Lu ◽  
Tao Li Xiao
Keyword(s):  
Finite Element ◽  
Regression Analysis ◽  
Finite Element Model ◽  
Element Model ◽  
Concrete Pavement ◽  
The Other ◽  
Tension Stress ◽  
Statistical Regression ◽  
Cement Concrete ◽  
Cement Concrete Pavement

Special load has produced serious damage to the concrete pavement because of the great gross weight and heavy axle load, but the present specification has not mentioned this kind of load. On this occasion, Several conditions of critical load are identified through ANSYS finite element model analysis and the formula through statistical regression analysis to the bottom maximum tension stress is drawn up. Which can not only guide the concrete pavement design under the special load but also the result may be referred by the other kinds of engineering.

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.

The effect of hirudotherapy on cerebral circulatory homeostasis in patients with genital endometriosis

2020 ◽  
pp. 58-66
Author(s):  
Ya. I. Uraeva ◽  
I. I. Ivanova ◽  
N. N. Lazarenko ◽  
E. V. Filatova ◽  
I. A. Pankova ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Drug Therapy ◽  
Cerebral Circulation ◽  
The State ◽  
Control Group ◽  
Complex Treatment ◽  
Statistical Regression ◽  
Treatment Results ◽  
Standard Drug ◽  
Before And After

The results of the treatment of women (n = 94) suffering from genital endometriosis are presented. The first (control, n = 30) group of women received standard drug therapy; the second (main, n = 64) group of women additionally had hirudotherapy procedures using medical leeches. The course of treatment consisted of 10–12 procedures. The state of cerebral circulation was assessed according to the rheoencephalography data before and after the treatment, as well as after 1, 3, 6, and 9 months. As a result, in patients in the 2-nd (main) group receiving complex treatment, the state of cerebral circulation improved signifi cantly. Moreover, according to the statistical regression analysis, it was possible to predict its further decrease by two periods ahead, compared with the treatment results in patients in the 1-st (control) group.

ERROR BOUNDED VARIABLE DISTANCE OFFSET OPERATOR FOR FREE FORM CURVES AND SURFACES

1991 ◽  
Vol 01 (01) ◽  
pp. 67-78 ◽  
Author(s):  
GERSHON ELBER ◽  
ELAINE COHEN
Keyword(s):  
Approximation Algorithms ◽  
Error Bound ◽  
Free Form ◽  
Global Error Bound ◽  
New Methods ◽  
Curves And Surfaces ◽  
Polygon Mesh ◽  
Finite Set ◽  
Variable Distance ◽  
Improved Accuracy

Most offset approximation algorithms for freeform curves and surfaces may be classified into two main groups. The first approximates the curve using simple primitives such as piecewise arcs and lines and then calculates the (exact) offset operator to this approximation. The second offsets the control polygon/mesh and then attempts to estimate the error of the approximated offset over a region. Most of the current offset algorithms estimate the error using a finite set of samples taken from the region and therefore can not guarantee the offset approximation is within a given tolerance over the whole curve or surface. This paper presents new methods to globally bound the error of the approximated offset of freeform curves and surfaces and then automatically derive new approximations with improved accuracy. These tools can also be used to develop a global error bound for a variable distance offset operation and to detect and trim out loops in the offset.

scholarly journals A new genetic method to predict the prognostic outcome of melanoma

2020 ◽  
Author(s):  
Hong GuoHu ◽  
Guan Qing ◽  
Luo XinHua
Keyword(s):  
Regression Analysis ◽  
Risk Score ◽  
Genetic Risk ◽  
Cox Regression ◽  
Genetic Risk Score ◽  
Biological Processes ◽  
Statistical Regression ◽  
Cox Regression Analysis ◽  
Genetic Method ◽  
Prognostic Outcome

AbstractCutaneous melanoma is quite often encountered in dermato-oncology. This paper describes a new genetic method to predict the prognostic outcome of melanoma. Data were collected from the TCGA databases. According to tumor progression status, the data were divided into two groups to evaluate the significant biological processes and key genes influencing the outcome of melanoma using a bioinformatics method. By adopting a statistical regression analysis method, a novel score based on the contributing genes was developed. Cox regression analysis was used to validate the effectiveness of the genetic risk score in predicting the outcome. Seven biological processes associated with melanocytes were identified. A protein-protein interactions network showed that 27 functional genes were associated with the outcome of melanoma. Among these, three genes (COL17A1, ITGA6, and SPRR2F) were used to calculate the genetic risk score, which was regarded as an independent and effective risk factor for disease progression or overall survival in melanoma.

Semi-automatic system for defining free-form curves and surfaces

1983 ◽  
Vol 15 (2) ◽  
pp. 65-72 ◽  
Author(s):  
Pierre E. Bézier ◽  
Salah Sioussiou
Keyword(s):  
Automatic System ◽  
Free Form ◽  
Curves And Surfaces
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