A COVERING PROJECTION FOR ROBOT NAVIGATION UNDER STRONG ANISOTROPY

2010 ◽  
Vol 20 (05) ◽  
pp. 511-525
Author(s):  
ANDREA ANGHINOLFI ◽  
LUCA COSTA ◽  
MASSIMO FERRI ◽  
ENRICO VIARANI
Keyword(s):  
Path Length ◽  
Robot Navigation ◽  
Synthetic Data ◽  
Riemannian Metric ◽  
Strong Anisotropy ◽  
Optimization Criteria ◽  
Optimal Paths ◽  
Different Types ◽  
Covering Projection ◽  
German Researcher

Path planning can be subject to different types of optimization. Some years ago a German researcher, U. Leuthäusser, proposed a new variational method for reducing most types of optimization criteria to one and the same: minimization of path length. This can be done by altering the Riemannian metric of the domain, so that optimal paths (with respect to whatever criterion) are simply seen as shortest. This method offers an extra feature, which has not been exploited so far: it admits direction–dependent criteria. In this paper we make this feature explicit, and apply it to two different anisotropic settings. One is that of different costs for different directions: E.g. the situation of a countryside scene with ploughed fields. The second is dependence on oriented directions, which is called here "strong" anisotropy: the typical scene is that of a hill side. A covering projection solves the additional difficulty. We also provide some experimental results on synthetic data.

A Rat-Robot Control System Based on Optogenetics

2013 ◽  
Vol 461 ◽  
pp. 848-852 ◽  
Author(s):  
Song Chao Guo ◽  
Hong Zhou ◽  
Yue Ming Wang ◽  
Xiao Xiang Zheng ◽  
Ke Di Xu
Keyword(s):  
Control System ◽  
Electrical Activity ◽  
Real Time ◽  
Navigation System ◽  
Robot Control ◽  
Robot Navigation ◽  
Freezing Behavior ◽  
Robot System ◽  
Optical Stimulation ◽  
Different Types

We developed a rat-robot system based on optogenetic techniques for the precise freezing behavior. Rat-robots were built up by optogenetic modulation at the dlPAG of rat brains. We conducted track navigation for the rat-robots and found they were able to exhibit precise freezing at given positions with high spatiotemporal accuracy. Different types of optical stimulation were compared and their influence on the rat-robots was investigated. Furthermore we recorded the neural electrical activity in real time during the optical stimulation. The system could be used to explore the mechanism of freezing behaviors and to build up a more integrated rat-robot navigation system based on optical modulations.

scholarly journals A survey of qualitative spatial representations

2013 ◽  
Vol 30 (1) ◽  
pp. 106-136 ◽  
Author(s):  
Juan Chen ◽  
Anthony G. Cohn ◽  
Dayou Liu ◽  
Shengsheng Wang ◽  
Jihong Ouyang ◽  
...  
Keyword(s):  
Spatial Representation ◽  
Spatial Databases ◽  
Robot Navigation ◽  
Spatial Relations ◽  
Spatial Representations ◽  
Language Understanding ◽  
Different Types ◽  
Qualitative Spatial Representation ◽  
Autonomous Robot Navigation ◽  
Future Work

AbstractRepresentation and reasoning with qualitative spatial relations is an important problem in artificial intelligence and has wide applications in the fields of geographic information system, computer vision, autonomous robot navigation, natural language understanding, spatial databases and so on. The reasons for this interest in using qualitative spatial relations include cognitive comprehensibility, efficiency and computational facility. This paper summarizes progress in qualitative spatial representation by describing key calculi representing different types of spatial relationships. The paper concludes with a discussion of current research and glimpse of future work.

scholarly journals The algebra of parallel endomorphisms of a pseudo-Riemannian metric: semi-simple part

2015 ◽  
Vol 159 (2) ◽  
pp. 219-237 ◽  
Author(s):  
CHARLES BOUBEL
Keyword(s):  
Riemannian Manifold ◽  
Associative Algebra ◽  
Ricci Curvature ◽  
Holonomy Group ◽  
Simple Algebra ◽  
Riemannian Metric ◽  
Generic Type ◽  
Simple Part ◽  
Different Types ◽  
Simple Algebras

AbstractOn a (pseudo-)Riemannian manifold (${\mathcal M}$, g), some fields of endomorphisms i.e. sections of End(T${\mathcal M}$) may be parallel for g. They form an associative algebra $\mathfrak e$, which is also the commutant of the holonomy group of g. As any associative algebra, $\mathfrak e$ is the sum of its radical and of a semi-simple algebra $\mathfrak s$. Here we study $\mathfrak s$: it may be of eight different types, including the generic type $\mathfrak s$ = ${\mathbb R}$ Id, and the Kähler and hyperkähler types $\mathfrak s$ ≃ ${\mathbb C}$ and $\mathfrak s$ ≃ ${\mathbb H}$. This is a result on real, semi-simple algebras with involution. For each type, the corresponding set of germs of metrics is non-empty; we parametrize it. We give the constraints imposed to the Ricci curvature by parallel endomorphism fields.

Implementation of a hexapod mobile robot with a fuzzy controller

Robotica ◽  
2005 ◽  
Vol 23 (6) ◽  
pp. 681-688 ◽  
Author(s):  
Makoto Kern ◽  
Peng-Yung Woo
Keyword(s):  
Fuzzy Logic ◽  
Mobile Robot ◽  
Fuzzy Controller ◽  
Robot Navigation ◽  
Fuzzy Rule ◽  
Sensor Data ◽  
Rule Base ◽  
Fuzzy Rule Base ◽  
Different Types ◽  
Autonomous Robot Navigation

Fuzzy logic has features that are particular attractive in light of the problems posed by autonomous robot navigation. Fuzzy logic allows us to model different types of uncertainty and imprecision. In this paper, the implementation of a hexapod mobile robot with a fuzzy controller navigating in unknown environments is presented. The robot, MKIII, interprets input sensor data through the comparison of values in its fuzzy rule base and moves accordingly to avoid obstacles. Results of trial run experiments are presented.

scholarly journals Target-Decoy MineR for determining the biological relevance of variables in noisy data sets

2020 ◽  
Author(s):  
Cesaré Ovando-Vázquez ◽  
Daniel Cázarez-García ◽  
Robert Winkler
Keyword(s):  
False Positive Rate ◽  
Synthetic Data ◽  
Noisy Data ◽  
Machine Learning Algorithms ◽  
Artificial Noise ◽  
Data Sets ◽  
Biological Relevance ◽  
Different Types ◽  
Positive Rate ◽  
Sensitivity Specificity

AbstractMachine learning algorithms excavate important variables from biological big data. However, deciding on the biological relevance of identified variables is challenging. The addition of artificial noise, ‘decoy’ variables, to raw data, ‘target’ variables, enables calculating a false-positive rate (FPR) and a biological relevance probability (BRp) for each variable rank. These scores allow the setting of a cut-off for informative variables can be defined, depending on the required sensitivity/ specificity of a scientific question. We demonstrate the function of the Target-Decoy MineR (TDM) with synthetic data and with experimental metabolomics results. The Target-Decoy MineR is suitable for different types of quantitative data in tabular format. An implementation of the algorithm in R is freely available from https://bitbucket.org/cesaremov/targetdecoy_mining/.

scholarly journals An Empirical Comparative Study of Instance-based Schema Matching

2018 ◽  
Vol 10 (3) ◽  
pp. 1266
Author(s):  
Mogahed Alzeber ◽  
Ali A. Alwan ◽  
Azlin Nordin ◽  
Abedallah Zaid Abualkishik
Keyword(s):  
Comparative Study ◽  
Regular Expression ◽  
Synthetic Data ◽  
Schema Matching ◽  
Data Sets ◽  
Different Types ◽  
Semantic Techniques ◽  
Matching Techniques ◽  
Accurate Matching ◽  
Match Accuracy

<span lang="EN-US">The main issue concern of schema matching is how to support the merging decision by providing matching between attributes of different schemas. There have been many works in the literature toward utilizing database instances to detect the correspondence between attributes. Most of these previous works aim at improving the match accuracy. We observed that no technique managed to provide an accurate matching for different types of data. In other words, some of the techniques treat numeric values as strings. Similarly, other techniques process textual instance, as numeric, and this negatively influences the process of discovering the match and compromising the matching result. Thus, a practical comparative study between syntactic and semantic techniques is needed. The study emphasizes on analyzing these techniques to determine the strengths and weaknesses of each technique. This paper aims at comparing two different instance-based matching techniques, namely: (i) regular expression and (ii) Google similarity to identify the match between attributes. Several analyses have been conducted on real and synthetic data sets to evaluate the performance of these techniques with respect to Precision (P), Recall (R) and F-Measure.</span>

scholarly journals Data Assimilation for Bathymetry Estimation at a Tidal Inlet

2016 ◽  
Vol 33 (10) ◽  
pp. 2145-2163 ◽  
Author(s):  
S. Moghimi ◽  
H. T. Özkan-Haller ◽  
G. W. Wilson ◽  
A. Kurapov
Keyword(s):  
Data Assimilation ◽  
Synthetic Data ◽  
Tidal Inlet ◽  
Current Data ◽  
Radar System ◽  
Surface Velocity ◽  
Tidal Circulation ◽  
X Band ◽  
Different Types ◽  
Synthetic Aperture Radar System

AbstractThis study involved developing and testing a data assimilation framework that accommodates different types of geophysical ocean data (i.e., surface velocity and wave information) and provides an estimation of the bathymetry of a mixed-energy tidal inlet. This framework was successfully applied to a highly variable tidal environment using synthetic data (twin test). The synthetic data consisted of surface velocity components associated with the tidal circulation and wavenumber–frequency pairs of incoming surface gravity waves that mimic data that could be derived from an airborne synthetic aperture radar system and a tower-mounted X-band radar system, respectively. The present ensemble-based assimilation framework has previously been applied in both wave-dominated coastal and current-dominated riverine environments. In contrast, the inlet environment is neither wave nor current dominated. The assimilation of wave and current data together was most useful to obtain a skillful estimate of the spatial map of bathymetry.

AN INTEGRATED LINEAR TECHNIQUE FOR POSE ESTIMATION FROM DIFFERENT GEOMETRIC FEATURES

1999 ◽  
Vol 13 (05) ◽  
pp. 705-733 ◽  
Author(s):  
QIANG JI ◽  
MAURO S. COSTA ◽  
ROBERT M. HARALICK ◽  
LINDA G. SHAPIRO
Keyword(s):  
Least Squares ◽  
Pose Estimation ◽  
Synthetic Data ◽  
Direct Methods ◽  
Geometric Features ◽  
Linear Least Squares ◽  
Linear Framework ◽  
Different Types ◽  
Geometric Entity ◽  
Linear Technique

Existing linear solutions for the pose estimation (or exterior orientation) problem suffer from a lack of robustness and accuracy partially due to the fact that the majority of the methods utilize only one type of geometric entity and their frameworks do not allow simultaneous use of different types of features. Furthermore, the orthonormality constraints are weakly enforced or not enforced at all. We have developed a new analytic linear least-squares framework for determining pose from multiple types of geometric features. The technique utilizes correspondences between points, between lines and between ellipse–circle pairs. The redundancy provided by different geometric features improves the robustness and accuracy of the least-squares solution. A novel way of approximately imposing orthonormality constraints on the sought rotation matrix within the linear framework is presented. Results from experimental evaluation of the new technique using both synthetic data and real images reveal its improved robustness and accuracy over existing direct methods.

Three-dimensional waypoint following for fixed-wing unmanned aerial vehicles in obstacle-filled environments

2019 ◽  
Vol 234 (3) ◽  
pp. 640-654
Author(s):  
Nikhil Kumar Singh ◽  
Sikha Hota
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Optimal Path ◽  
Three Dimensional ◽  
Computation Time ◽  
Two Dimensional ◽  
Aerial Vehicles ◽  
Optimal Paths ◽  
Straight Line ◽  
Different Types ◽  
Simulation Results

The paper computes optimal paths for fixed-wing unmanned aerial vehicles with bounded turn radii to follow a series of waypoints with specified directions in a three-dimensional obstacle-filled environment. In the existing literature, it was proved that the optimal path is of circular turn–straight line–circular turn (CSC) type for two consecutive waypoint configurations, when the points are sufficiently far apart and there is no obstacle in the field. The maximum of all minimum turn radii corresponding to all possible two-dimensional circular maneuvers was used for both the initial and final turns to develop the CSC-type paths. But, this paper considers the minimum turn radii for initial and final turns, corresponding to the maneuvering planes and which produces shorter CSC-type paths. In an obstacle-filled environment the shortest path may collide with obstacles, so a strategy is proposed to switch to the next best path that does not collide with obstacles. Using this technique, a series of waypoints is followed in the presence of obstacles of different types, for example, cylindrical, hemispherical, and spherical in shapes with different sizes. Finally, simulation results are presented to show the efficiency of the algorithm for obstacle avoidance. The computation time listed here indicates the potentiality of this algorithm for implementation in real time.

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