摘要:

A new robot simulator JC‐1 is used as a control software development tool in a project in progress where an intelligent wheelchair for a blind user is being developed. The intelligent wheelchair is planned to be able to fulfill simple symbolic commands like “follow wall” or “follow object” and using the JC‐1 simulator an evaluation team which includes e.g. the user, a rehabilitation engineer and a software engineer, can check control algorithms and user interface routines before constructing a real wheelchair prototype. The JC‐1 simulator models the environment using simplified boundary‐ representation where objects, robot sensors and actuators are presented as symbolic objects in the graphics data‐base of the simulator. In the JC‐1 simulator a robot controller under development controls the motion of the graphical model of the robot while simulator commands or other robot controllers can be used to control the movement of disturbing obstacles. Computer graphics animation and simulation help to find fundamental design errors at an early design stage and as this paper suggests, enable the user of the final product to take part in to the designing process of the robot controller. Benefits and difficulties of using computer graphics simulation in the wheelchair development pr

ISSN:0167-7055    

DOI:10.1111/1467-8659.1040285

出版商:Blackwell Science Ltd    

年代:1991

数据来源: WILEY

摘要:

This paper presents a new scheme to integrate the declarative approach to graphics and object‐oriented data modelling techniques to form a fruitful symbiosis for constraint‐based graphics database systems. It has rich modelling constructs to describe graphics data and allows sharing of representation. It also provides useful mechanisms for management of integrity constraints. We have also identified important classes of constraints in the context of object‐oriented graphics database systems. Examples are given for maintenance of constraints at the time of insertion, deletion and modific

ISSN:0167-7055    

DOI:10.1111/1467-8659.1040297

出版商:Blackwell Science Ltd    

年代:1991

数据来源: WILEY

摘要:

This paper describes first results of a test implementation that implements the new multivariate B‐splines as recently developed by Dahmen et al. 10for quadratics and cubics. The surface scheme is based on blending functions and control points and allows the modelling ofCk− 1‐continuous piecewise polynomial surfaces of degreekover arbitrary triangulations of the parameter plane. The surface scheme exhibits both affine invariance and the convex hull property, and the control points can be used to manipulate the shape of the surface locally. Additional degrees of freedom in the underlying knot net allow for the modelling of discontinuities. Explicit formulas are given for the representation of polynomials and piecewise polynomials as linear combinations of B‐

ISSN:0167-7055    

DOI:10.1111/1467-8659.1040309

出版商:Blackwell Science Ltd    

年代:1991

数据来源: WILEY

摘要:

With any word over the alphabetΠ={r, r̄, u, ū}, we associate a connected picture in the following manner: the reading of each letter of this word induces a unit line:r (r̄, u, ū respectively)stands for a right (left, up, down respectively) move. We present a rewriting system which can yield, from any word over Π, all the words describing the same picture. Particularly, we give an algorithm to find a minimal word describing a given picture: this word represents the shortest way to draw this picture without

ISSN:0167-7055    

DOI:10.1111/1467-8659.1040319

出版商:Blackwell Science Ltd    

年代:1991

数据来源: WILEY

摘要:

This informal note presents computational recipes for producing visually interesting surfaces.

ISSN:0167-7055    

DOI:10.1111/1467-8659.1040329

出版商:Blackwell Science Ltd    

年代:1991

数据来源: WILEY

摘要:

Visually interesting chaotic attractors resembling sculpture are described.

ISSN:0167-7055    

DOI:10.1111/1467-8659.1040333

出版商:Blackwell Science Ltd    

年代:1991

数据来源: WILEY