Shadia Elgazzar
National Research Council
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Featured researches published by Shadia Elgazzar.
international conference on robotics and automation | 1985
Shadia Elgazzar
Efficient solutions for the kinematic positions, velocities, and accelerations for the six-degree-of-freedom PUMA 560 robot are presented. The kinematic problem is defined as the transformation from the Cartesian space to the joint space and vice versa. The solution method is based on a method that fully exploits the special geometry of the robot in the derivation of the solution. Special attention is given to the arm configuration in both directions of the transformation.
IEEE Transactions on Instrumentation and Measurement | 1994
Larry Korba; Shadia Elgazzar; Timothy Welch
Sensors based on the ultrasonic, pulse-echo technique for measuring range have been the mainstay for robotic collision avoidance systems. Although these sensors have been successfully applied to both indoor and outdoor mobile robotic applications, certain disadvantages of these systems prompted our investigation of inexpensive sensors that use light to determine the range or presence of targets. A number of commercially available, light-based sensors are analyzed for application in a mobile robotic space application. The objective of the analysis is to develop a cost-effective, light-based ranging sensor for a collision avoidance system for an experimental Mars Rover. This paper presents some results from our investigation. >
IEEE Transactions on Instrumentation and Measurement | 1998
Shadia Elgazzar; Ramiro Liscano; François Blais; Andrew Miles
This paper investigates modeling indoor environments using a low-cost, compact, active-range camera, known as BIRIS, mounted onto a pan and tilt motor unit. The BIRIS sensor, developed at the National Research Council of Canada, is a rugged small camera with no moving parts. The objectives of this paper are to describe and demonstrate the viability of the use of a low-cost range sensor in the domain of indoor environment modeling; to present the results of processing three-dimensional (3-D) data to build a virtual environment for navigation and visualization; and, to analyze and outline the advantages and limitations encountered when scanning large indoor environments.
instrumentation and measurement technology conference | 1993
Larry Korba; Shadia Elgazzar; T. Welch
The authors investigate cost-effective sensors that are based on light sensing techniques. A number of light-based sensors were analyzed for use in a mobile robotic application. The objective of the analysis was to develop a cost-effective light-based ranging sensor that may be used as an alternative to sonar. Commercial optoelectronic sensors priced under
instrumentation and measurement technology conference | 1997
Shadia Elgazzar; Ramiro Liscano; Francois Blais; A. Miles
500 and several different camera auto-focus systems were examined to determine their suitability for the application. A description of the tests used in the assessments followed by a description of each sensor are included.<<ETX>>
ICCBSS'05 Proceedings of the 4th international conference on COTS-Based Software Systems | 2005
Shadia Elgazzar; Anatol W. Kark; Erik Putrycz; Mark R. Vigder
This paper investigates modeling indoor environments using a low-cost compact active range camera, known as BIRIS, mounted onto a pan and tilt motor unit. The BIRIS sensor, developed at the National Research Council of Canada, is a rugged small camera with no moving parts. The contributions of this paper are mainly in three areas: it demonstrates the viability of the use of a low-cost range sensor in the domain of indoor environment modeling; it presents the of processing 3-D data to build a virtual environment for navigation and visualization; and, it analyses and outlines the advantages and and limitations encountered when scanning large indoor environments.
Optics for Productivity in Manufacturing | 1994
Vania Conan; Pierre Boulanger; Shadia Elgazzar
Organizations that are acquiring a COTS based system must adapt many of their acquisition process activities that are traditionally used for acquiring non-COTS based systems. Much of this adaptation becomes quite difficult within government environments where the process is often constrained by government rules and regulations. This paper provides an experience report on COTS based acquisition for a government agency during the early stages of the process. The impact on requirements engineering and the steps for developing the Request For Proposal (RFP) and evaluating the proposals are outlined. The parties involved in the acquisition process are identified, and their relationship within a project governance structure are discussed. The final discussion provides some guidance as to how the early stages of the acquisition process should be adapted to minimize risk through the project.
Canadian Electrical Engineering Journal | 1984
Shadia Elgazzar; Steve Onyshko
The ability to estimate the position of a mobile vehicle is a key task for navigation over large distances in complex indoor environments such as nuclear power plants. Schematics of the plants are available, but they are incomplete, as real settings contain many objects, such as pipes, cables or furniture, that mask part of the model. The position estimation method described in this paper matches 3-D data with a simple schematic of a plant. It is basically independent of odometry information and viewpoint, robust to noisy data and spurious points and largely insensitive to occlusions. The method is based on a hypothesis/verification paradigm and its complexity is polynomial; it runs in (Omicron) (m4n4), where m represents the number of model patches and n the number of scene patches. Heuristics are presented to speed up the algorithm. Results on real 3-D data show good behavior even when the scene is very occluded.
systems man and cybernetics | 1998
Ramiro Liscano; Andrew Wong; Shadia Elgazzar
The problem of finding the optimal control sequences for pulse frequency modulated (PFM) systems with quadratic performance indices and fixed final time is considered. A method for the implementation of the on-line controller and the modulator, using the modified maximum principles (MMP), is presented and illustrated by an example.
Canadian Electrical Engineering Journal | 1981
Shadia Elgazzar
This article introduces a representation known as Bayesian attributed hypergraphs (BAHGs) that are based on the integration of Bayesian networks and attributed hypergraphs. BAHGs are an augmentation to attributed hypergraphs that allow for the management of uncertainty, using Bayesian theory, and can reason about formations from the sensory data using simple graph operators. They allow for the creation of multiple instantiations of Bayesian networks while maintaining single instantiation of nodes that represent the same event. This unification of uncertainty management and attributed hypergraphs removes the need of maintaining and synchronizing between a representation for managing uncertainty and another to manage declarative knowledge. A formalism for the construction of a BAHG for image understanding is presented based on the decomposition by parts methodology and the use of geometric constraints among feature sets. An example is presented that performs perceptual grouping among fragmented 3-D surfaces in an attempt to group the surfaces into corners and continuous surfaces.