Effects of line length, orientation angle, and drawing direction on the straight‐line drawing performance of elderly Taiwanese adults during iPad use

2019 ◽  
Vol 30 (2) ◽  
pp. 140-146
Author(s):  
Chia‐Chen Wu ◽  
Kuo‐Chen Huang
Keyword(s):  
Line Drawing ◽  
Orientation Angle ◽  
Line Length ◽  
Drawing Direction ◽  
Straight Line

scholarly journals THE POINT-SET EMBEDDABILITY PROBLEM FOR PLANE GRAPHS

2013 ◽  
Vol 23 (04n05) ◽  
pp. 357-395 ◽  
Author(s):  
THERESE BIEDL ◽  
MARTIN VATSHELLE
Keyword(s):  
Planar Graph ◽  
Planar Graphs ◽  
Line Drawing ◽  
Np Hard ◽  
Bounded Treewidth ◽  
Straight Line ◽  
Triangulated Graphs ◽  
Point Set ◽  
Fixed Embedding ◽  
Set Of Points

In this paper, we study the point-set embeddability problem, i.e., given a planar graph and a set of points, is there a mapping of the vertices to the points such that the resulting straight-line drawing is planar? It was known that this problem is NP-hard if the embedding can be chosen, but becomes polynomial for triangulated graphs of treewidth 3. We show here that in fact it can be answered for all planar graphs with a fixed combinatorial embedding that have constant treewidth and constant face-degree. We prove that as soon as one of the conditions is dropped (i.e., either the treewidth is unbounded or some faces have large degrees), point-set embeddability with a fixed embedding becomes NP-hard. The NP-hardness holds even for a 3-connected planar graph with constant treewidth, triangulated planar graphs, or 2-connected outer-planar graphs. These results also show that the convex point-set embeddability problem (where faces must be convex) is NP-hard, but we prove that it becomes polynomial if the graph has bounded treewidth and bounded maximum degree.

Motion feasibility of a wheeled vehicle with a steering angle limit

Robotica ◽  
1994 ◽  
Vol 12 (3) ◽  
pp. 217-226 ◽  
Author(s):  
Yongji Wang ◽  
J.A. Linnett ◽  
J.W. Roberts
Keyword(s):  
Reference Point ◽  
Orientation Angle ◽  
Feasibility Problem ◽  
Deviation Angle ◽  
Steering Angle ◽  
Wheeled Vehicle ◽  
Straight Line ◽  
Steering Mechanism ◽  
Simulation Results ◽  
The Relationship

SUMMARYIn the problem of automatically controlling a wheeled vehicle so that a given reference point on the vehicle follows a prescribed path, several factors determine how the task can be accomplished; they are the shape of the path, the initial orientation angle, the steering angle limit and the position of the reference point on the vehicle. If the required steering angle exceeds the limit set by the steering mechanism or the required orientation angle is discontinuous at any point along the path, then the path cannot be followed. This paper investigates this motion feasibility problem, taking steering angle limit into consideration. First of all, we determine the dependence of the continuity of the orientation angle, steering angle and their derivatives on the continuity of the reference path and its derivatives, then discuss .the relationship between the steering angle limit and the feasible deviation angle intervals. Furthermore, we analyze in detail two typical motions, namely straight line motion and circular motion; some simulation results have been given based on a practical vehicle dimension.

scholarly journals The effect of ignition protocol on grassfire development

2020 ◽  
Vol 29 (1) ◽  
pp. 70
Author(s):  
Duncan Sutherland ◽  
Jason J. Sharples ◽  
Khalid A. M. Moinuddin
Keyword(s):  
Wind Speed ◽  
Temporal Resolution ◽  
Line Length ◽  
Forward Rate ◽  
High Temporal Resolution ◽  
Quasi Equilibrium ◽  
Rate Of Spread ◽  
Straight Line ◽  
Shortest Distance ◽  
Physics Based Simulation

The effect of ignition protocol on the development of grassfires is investigated using physics-based simulation. Simulation allows measurement of the forward rate of spread of a fire as a function of time at high temporal resolution. Two ignition protocols are considered: the inward ignition protocol, where the ignition proceeds in a straight line from the edges of the burnable fire plot to the centre of the plot; and the outwards ignition protocol, where the ignition proceeds from the centre of the burnable fire plot to the edges of the plot. In addition to the two ignition protocols, the wind speed, time taken for the ignition to be completed and ignition line length are varied. The rate of spread (R) of the resultant fires is analysed. The outwards ignition protocol leads to an (approximately) monotonic increase in R, whereas the inward ignition protocol can lead to a peak in R before decreasing to the quasi-equilibrium R. The fires simulated here typically take 50m from the ignition line to develop a quasi-equilibrium R. The results suggest that a faster ignition is preferable to achieve a quasi-equilibrium R in the shortest distance from the ignition line.

scholarly journals The End of the Line for a Brain-Damaged Model of Unilateral Neglect

1997 ◽  
Vol 9 (2) ◽  
pp. 171-190 ◽  
Author(s):  
Michael C. Mozer ◽  
Peter W. Halligan ◽  
John C. Marshall
Keyword(s):  
Right Hemisphere ◽  
Orientation Angle ◽  
Line Length ◽  
The Body ◽  
Line Bisection ◽  
Simple Task ◽  
Unilateral Neglect ◽  
Related Disorder ◽  
On Line ◽  
The Right

For more than a century, it has been known that damage to the right hemisphere of the brain can cause patients to be unaware of the contralesional side of space. This condition, known as unilateral neglect, represents a collection of clinically related spatial disorders characterized by the failure in free vision to respond, explore, or orient to stimuli predominantly located on the side of space opposite the damaged hemisphere. Recent studies using the simple task of line bisection, a conventional diagnostic test, have proven surprisingly revealing with respect to the spatial and attentional impairments involved in neglect. In line bisection, the patient is asked to mark the midpoint of a thin horizontal lie on a sheet of paper. Neglect patients generally transect far to the right of the center. Extensive studies of line bisection have been conducted, manipulating-among other factors-line length, orientation, and position. We have simulated the pattern of results using an existing computational model of visual perception and selective attention called MORSEL (Mozer, 1991). MORSEL has already been used to model data in a related disorder, neglect dyslexia (Mozer & Behrmann, 1990). In this earlier work, MORSEL was “lesioned” in accordance with the damage we suppose to have occurred in the brains of neglect patients. The same model and lesion can simulate the detailed pattern of performance on line bisection, including the following observations: (1) no consistent across-subject bias is found in normals; (2) transection displacements are proportional to line length in neglect patients; (3) variability of displacements is proportional to line length, in both normals and patients; (4) position of the lines with respect to the body or the page on which they are drawn has little effect; and (5) for lines drawn at different orientations, displacements are proportional to the cosine of the orientation angle. MORSEL fails to account for one observation: across patients, the variability of displacements for a particular line length is roughly proportional to mean displacement. Nonetheless, the overall fit of the model is sufficiently good that we believe MORSEL can be used as a diagnostic tool to characterize the specific nature of a patient's deficit, and thereby has potential down the line in therapy.

Sign in / Sign up

Export Citation Format

Share Document