Implicit Representation of Bigranular Rules for Multigranular Data

2018 ◽  
pp. 372-389
Author(s):  
Stephen J. Hegner ◽  
M. Andrea Rodríguez
Keyword(s):  
Implicit Representation

Point set registration for assembly feature pose estimation using simulated annealing nested Gauss-Newton optimization

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kunyong Chen ◽  
Yong Zhao ◽  
Jiaxiang Wang ◽  
Hongwen Xing ◽  
Zhengjian Dong
Keyword(s):  
Simulated Annealing ◽  
Pose Estimation ◽  
Distance Metric ◽  
Implicit Representation ◽  
Registration Method ◽  
Content Type ◽  
Point Set Registration ◽  
Searching Strategy ◽  
Global Robustness ◽  
Point Set

Purpose This paper aims to propose a fast and robust 3D point set registration method for pose estimation of assembly features with few distinctive local features in the manufacturing process. Design/methodology/approach The distance between the two 3D objects is analytically approximated by the implicit representation of the target model. Specifically, the implicit B-spline surface is adopted as an interface to derive the distance metric. With the distance metric, the point set registration problem is formulated into an unconstrained nonlinear least-squares optimization problem. Simulated annealing nested Gauss-Newton method is designed to solve the non-convex problem. This integration of gradient-based optimization and heuristic searching strategy guarantees both global robustness and sufficient efficiency. Findings The proposed method improves the registration efficiency while maintaining high accuracy compared with several commonly used approaches. Convergence can be guaranteed even with critical initial poses or in partial overlapping conditions. The multiple flanges pose estimation experiment validates the effectiveness of the proposed method in real-world applications. Originality/value The proposed registration method is much more efficient because no feature estimation or point-wise correspondences update are performed. At each iteration of the Gauss–Newton optimization, the poses are updated in a singularity-free format without taking the derivatives of a bunch of scalar trigonometric functions. The advantage of the simulated annealing searching strategy is combined to improve global robustness. The implementation is relatively straightforward, which can be easily integrated to realize automatic pose estimation to guide the assembly process.

scholarly journals Why is the Duration of Imagined Walking Underproduced? A dual-representation view on the mental imagery of locomotion

2018 ◽  
Author(s):  
Naohide Yamamoto ◽  
Dagmara E. Mach ◽  
John W. Philbeck ◽  
Jennifer Van Pelt
Keyword(s):  
Mental Imagery ◽  
Temporal Structure ◽  
Explicit Representation ◽  
Production Task ◽  
Dual Representation ◽  
Implicit Representation ◽  
Time Production ◽  
Spatial Tasks ◽  
Motor Representations ◽  
Implicit Representations

Generally, imagining an action and physically executing it are thought to be controlled by common motor representations. However, imagined walking to a previewed target tends to be terminated more quickly than real walking to the same target, raising a question as to what representations underlie the two modes of walking. To address this question, the present study put forward a hypothesis that both explicit and implicit representations of gait are involved in imagined walking, and further proposed that the underproduction of imagined walking duration largely stems from the explicit representation due to its susceptibility to a general undershooting tendency in time production (i.e., the error of anticipation). Properties of the explicit and implicit representations were examined by manipulating their relative dominance during imagined walking through concurrent bodily motions, and also by using non-spatial tasks that extracted the temporal structure of imagined walking. Results showed that the duration of imagined walking subserved by the implicit representation was equal to that of real walking, and a time production task exhibited an equivalent underproduction bias as in imagined walking tasks that were based on the explicit representation. These findings are interpreted as evidence for the dual-representation view of imagined walking.

scholarly journals Intact implicit representation of object 3D structure in object agnosia

2015 ◽  
Vol 15 (12) ◽  
pp. 1099 ◽  
Author(s):  
Erez Freud ◽  
Tzvi Ganel ◽  
Galia Avidan ◽  
Marlene Behrmann
Keyword(s):  
3D Structure ◽  
Implicit Representation

Computerized Implicit Representation Test

2015 ◽  
Author(s):  
Craig Piers ◽  
Ryan J. Piers ◽  
J. Christopher Fowler ◽  
J. Christopher Perry
Keyword(s):  
Implicit Representation

Robust and efficient forward, differential, and inverse kinematics using dual quaternions

2020 ◽  
pp. 027836492093194
Author(s):  
Neil T Dantam
Keyword(s):  
Inverse Kinematics ◽  
Forward Kinematics ◽  
Robot Kinematics ◽  
Dual Numbers ◽  
Dual Quaternion ◽  
Implicit Representation ◽  
Alternative Representation ◽  
Transformation Matrices ◽  
Dual Quaternions ◽  
Efficient Representation

Modern approaches for robot kinematics employ the product of exponentials formulation, represented using homogeneous transformation matrices. Quaternions over dual numbers are an established alternative representation; however, their use presents certain challenges: the dual quaternion exponential and logarithm contain a zero-angle singularity, and many common operations are less efficient using dual quaternions than with matrices. We present a new derivation of the dual quaternion exponential and logarithm that removes the singularity, we show an implicit representation of dual quaternions offers analytical and empirical efficiency advantages compared with both matrices and explicit dual quaternions, and we derive efficient dual quaternion forms of differential and inverse position kinematics. Analytically, implicit dual quaternions are more compact and require fewer arithmetic instructions for common operations, including chaining and exponentials. Empirically, we demonstrate a 30–40% speedup on forward kinematics and a 300–500% speedup on inverse position kinematics. This work relates dual quaternions with modern exponential coordinates and demonstrates that dual quaternions are a robust and efficient representation for robot kinematics.

scholarly journals An explicit representation for disappointment aversion and other betweenness preferences

2020 ◽  
Vol 15 (4) ◽  
pp. 1509-1546
Author(s):  
Simone Cerreia-Vioglio ◽  
David Dillenberger ◽  
Pietro Ortoleva
Keyword(s):  
Functional Equation ◽  
Expected Utility ◽  
General Result ◽  
Explicit Representation ◽  
Implicit Representation ◽  
Utility Representation ◽  
Disappointment Aversion

One of the most well known models of non‐expected utility is Gul's (1991) model of disappointment aversion. This model, however, is defined implicitly, as the solution to a functional equation; its explicit utility representation is unknown, which may limit its applicability. We show that an explicit representation can be easily constructed, using solely the components of the implicit representation. We also provide a more general result: an explicit representation for preferences in the betweenness class that also satisfy negative certainty independence (Dillenberger 2010) or its counterpart. We show how our approach gives a simple way to identify the parameters of the representation behaviorally and to study the consequences of disappointment aversion in a variety of applications.

scholarly journals The problem of detecting when two implicit plane algebraic curves are similar

2019 ◽  
Vol 29 (05) ◽  
pp. 775-793 ◽  
Author(s):  
Juan Gerardo Alcázar ◽  
Gema M. Díaz-Toca ◽  
Carlos Hermoso
Keyword(s):  
Computer Algebra ◽  
Computer Algebra System ◽  
Algebraic Curves ◽  
Deterministic Algorithm ◽  
Implicit Representation ◽  
Practical Performance

We make use of the complex implicit representation in order to provide a deterministic algorithm for checking whether or not two implicit algebraic curves are related by a similarity. The algorithm has been implemented in the computer algebra system Maple 2016. The implementation can be freely downloaded from the webpage of one of the authors. Examples and evidence of the good practical performance of the algorithm are given.

Stimulus-Specific Sequence Representation in Serial Reaction Time Tasks

2005 ◽  
Vol 58 (6) ◽  
pp. 1087-1101 ◽  
Author(s):  
Benjamin A. Clegg
Keyword(s):  
Reaction Time ◽  
Explicit Knowledge ◽  
Reaction Time Task ◽  
Serial Reaction Time ◽  
Specific Sequence ◽  
Response Latencies ◽  
Implicit Representation ◽  
Multiple Loci ◽  
Serial Reaction ◽  
Sequence Representation

Some recent evidence has favoured purely response-based implicit representation of sequences in serial reaction time tasks. Three experiments were conducted using serial reaction time tasks featuring four spatial stimuli mapped in categories to two responses. Deviant items from the expected sequence that required the expected response resulted in increased response latencies. The findings demonstrated a stimulus-specific form of representation that operates in the serial reaction time task. No evidence was found to suggest that the stimulus-specific learning was contingent on explicit knowledge of the sequence. Such stimulus-based learning would be congruent with a shortcut within an information-processing framework and, combined with other research findings, suggests that there are multiple loci for learning effects.

Implicit Solid Modeling for Mesh Free Analysis

2005 ◽  
Author(s):  
Ashok V. Kumar ◽  
Jongho Lee ◽  
Ravi Burla
Keyword(s):  
Solid Modeling ◽  
Step Function ◽  
Characteristic Functions ◽  
Implicit Representation ◽  
Implicit Equation ◽  
Hexahedral Elements ◽  
Unit Value ◽  
Mesh Free ◽  
Implicit Equations ◽  
Representation Scheme

In traditional solid modeling the boundaries of the solid are represented using parametric equations. Even though the application of implicit equations has also been explored, they have not been widely used. Interest has been rekindled recently due to application of implicit equations to mesh free engineering analysis. In this paper, an implicit representation scheme for solids is presented where the boundaries of primitive solids are defined using implicit equation of surfaces. To ensure that the equations are axis independent, the characteristic functions for the implicit equations are defined by interpolating within hexahedral elements. Primitive solids are defined by sweeping closed 2D profiles. The boundaries of these profiles are defined using implicit equations of curves. Implicit equations can be used for constructing “step function” of the primitives and their Boolean combinations. The step functions of a solid has a unit value inside the solid and zero outside and can be used for computing volume integrals needed for mesh free analysis.

scholarly journals Active contours using a constraint-based implicit representation

2005 ◽  
Author(s):  
Bryan S. Morse ◽  
Weiming Liu ◽  
Terry S. Yoo ◽  
Kalpathi Subramanian
Keyword(s):  
Active Contours ◽  
Implicit Representation
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