506,915 research outputs found
Experimental analysis of the accessibility of drawings with few segments
The visual complexity of a graph drawing is defined as the number of
geometric objects needed to represent all its edges. In particular, one object
may represent multiple edges, e.g., one needs only one line segment to draw two
collinear incident edges. We study the question if drawings with few segments
have a better aesthetic appeal and help the user to asses the underlying graph.
We design an experiment that investigates two different graph types (trees and
sparse graphs), three different layout algorithms for trees, and two different
layout algorithms for sparse graphs. We asked the users to give an aesthetic
ranking on the layouts and to perform a furthest-pair or shortest-path task on
the drawings.Comment: Appears in the Proceedings of the 25th International Symposium on
Graph Drawing and Network Visualization (GD 2017
Extended LTLvis Motion Planning interface (Extended Technical Report)
This paper introduces an extended version of the Linear Temporal Logic (LTL)
graphical interface. It is a sketch based interface built on the Android
platform which makes the LTL control interface more straightforward and
friendly to nonexpert users. By predefining a set of areas of interest, this
interface can quickly and efficiently create plans that satisfy extended plan
goals in LTL. The interface can also allow users to customize the paths for
this plan by sketching a set of reference trajectories. Given the custom paths
by the user, the LTL specification and the environment, the interface generates
a plan balancing the customized paths and the LTL specifications. We also show
experimental results with the implemented interface.Comment: 8 pages, 15 figures, a technical report for the 2016 IEEE
International Conference on Systems, Man, and Cybernetics (SMC 2016
Matching with Couples Revisited
It is well known that a stable matching in a many-to-one matching market with
couples need not exist. We introduce a new matching algorithm for such markets
and show that for a general class of large random markets the algorithm will
find a stable matching with high probability. In particular we allow the number
of couples to grow at a near-linear rate. Furthermore, truth-telling is an
approximated equilibrium in the game induced by the new matching algorithm. Our
results are tight: for markets in which the number of couples grows at a linear
rate, we show that with constant probability no stable matching exists
Algorithms and Complexity Results for Persuasive Argumentation
The study of arguments as abstract entities and their interaction as
introduced by Dung (Artificial Intelligence 177, 1995) has become one of the
most active research branches within Artificial Intelligence and Reasoning. A
main issue for abstract argumentation systems is the selection of acceptable
sets of arguments. Value-based argumentation, as introduced by Bench-Capon (J.
Logic Comput. 13, 2003), extends Dung's framework. It takes into account the
relative strength of arguments with respect to some ranking representing an
audience: an argument is subjectively accepted if it is accepted with respect
to some audience, it is objectively accepted if it is accepted with respect to
all audiences. Deciding whether an argument is subjectively or objectively
accepted, respectively, are computationally intractable problems. In fact, the
problems remain intractable under structural restrictions that render the main
computational problems for non-value-based argumentation systems tractable. In
this paper we identify nontrivial classes of value-based argumentation systems
for which the acceptance problems are polynomial-time tractable. The classes
are defined by means of structural restrictions in terms of the underlying
graphical structure of the value-based system. Furthermore we show that the
acceptance problems are intractable for two classes of value-based systems that
where conjectured to be tractable by Dunne (Artificial Intelligence 171, 2007)
Iterative Delegations in Liquid Democracy with Restricted Preferences
In this paper, we study liquid democracy, a collective decision making
paradigm which lies between direct and representative democracy. One main
feature of liquid democracy is that voters can delegate their votes in a
transitive manner so that: A delegates to B and B delegates to C leads to A
delegates to C. Unfortunately, this process may not converge as there may not
even exist a stable state (also called equilibrium). In this paper, we
investigate the stability of the delegation process in liquid democracy when
voters have restricted types of preference on the agent representing them
(e.g., single-peaked preferences). We show that various natural structures of
preferences guarantee the existence of an equilibrium and we obtain both
tractability and hardness results for the problem of computing several
equilibria with some desirable properties
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