40,514 research outputs found
CLPGUI: a generic graphical user interface for constraint logic programming over finite domains
CLPGUI is a graphical user interface for visualizing and interacting with
constraint logic programs over finite domains. In CLPGUI, the user can control
the execution of a CLP program through several views of constraints, of finite
domain variables and of the search tree. CLPGUI is intended to be used both for
teaching purposes, and for debugging and improving complex programs of
realworld scale. It is based on a client-server architecture for connecting the
CLP process to a Java-based GUI process. Communication by message passing
provides an open architecture which facilitates the reuse of graphical
components and the porting to different constraint programming systems.
Arbitrary constraints and goals can be posted incrementally from the GUI. We
propose several dynamic 2D and 3D visualizations of the search tree and of the
evolution of finite domain variables. We argue that the 3D representation of
search trees proposed in this paper provides the most appropriate visualization
of large search trees. We describe the current implementation of the
annotations and of the interactive execution model in GNU-Prolog, and report
some evaluation results.Comment: 16 pages; Alexandre Tessier, editor; WLPE 2002,
http://xxx.lanl.gov/abs/cs.SE/020705
On the practicality of global flow analysis of logic programs
This paper addresses the issue of the practicality of global flow analysis in logic program compilation, in terms of both speed and precision of analysis. It discusses design and implementation aspects of two practical abstract interpretation-based flow analysis systems: MA3, the MOO Andparallel Analyzer and Annotator; and Ms, an experimental mode inference system developed for SB-Prolog. The paper also provides performance data obtained from these implementations. Based on these results, it is concluded that the overhead of global flow analysis is not prohibitive, while the results of analysis can be quite precise and useful
TOR: modular search with hookable disjunction
Horn Clause Programs have a natural exhaustive depth-first procedural
semantics. However, for many programs this semantics is
ineffective. In order to compute useful solutions, one needs the
ability to modify the search method that explores the alternative
execution branches.
Tor, a well-defined hook into Prolog disjunction, provides this ability.
It is light-weight thanks to its library approach and efficient
because it is based on program transformation.
Tor is general enough to mimic search-modifying
predicates like ECLiPSe's search/6. Moreover, Tor supports
modular composition of search methods and other hooks.
The Tor library is already
provided and used as an add-on to SWI-Prolog.publisher: Elsevier
articletitle: Tor: Modular search with hookable disjunction
journaltitle: Science of Computer Programming
articlelink: http://dx.doi.org/10.1016/j.scico.2013.05.008
content_type: article
copyright: Copyright © 2013 Elsevier B.V. All rights reserved.status: publishe
Air Taxi Skyport Location Problem for Airport Access
Witnessing the rapid progress and accelerated commercialization made in
recent years for the introduction of air taxi services in near future across
metropolitan cities, our research focuses on one of the most important
consideration for such services, i.e., infrastructure planning (also known as
skyports). We consider design of skyport locations for air taxis accessing
airports, where we present the skyport location problem as a modified
single-allocation p-hub median location problem integrating choice-constrained
user mode choice behavior into the decision process. Our approach focuses on
two alternative objectives i.e., maximizing air taxi ridership and maximizing
air taxi revenue. The proposed models in the study incorporate trade-offs
between trip length and trip cost based on mode choice behavior of travelers to
determine optimal choices of skyports in an urban city. We examine the
sensitivity of skyport locations based on two objectives, three air taxi
pricing strategies, and varying transfer times at skyports. A case study of New
York City is conducted considering a network of 149 taxi zones and 3 airports
with over 20 million for-hire-vehicles trip data to the airports to discuss
insights around the choice of skyport locations in the city, and demand
allocation to different skyports under various parameter settings. Results
suggest that a minimum of 9 skyports located between Manhattan, Queens and
Brooklyn can adequately accommodate the airport access travel needs and are
sufficiently stable against transfer time increases. Findings from this study
can help air taxi providers strategize infrastructure design options and
investment decisions based on skyport location choices.Comment: 25 page
Senescence vs. sustenance: Evolutionary-demographic models of aging
Humans, and many other species, suffer senescence: mortality increases and fertility declines with adult age. Some species, however, enjoy sustenance: mortality and fertility remain constant. Here we develop simple but general evolutionary-demographic models to explain the conditions that favor senescence vs. sustenance. The models illustrate how mathematical demography can deepen understanding of the evolution of aging.aging, eusociality, evolution, fertility, hydra, mortality, senescence, sustenance
The Co-opting of Ethnic Studies in the American University: A Critical View
The birth of ethnic studies in the American university was accompanied by the politics and pedagogy of rage, pride, and mistrust for the then prevailing curricular academic structures and its tradition-bound, academically conservative gatekeepers. The campus take-overs, student demands, and confrontations were a common expression of the times, and concomitantly these were also shapers of the changing times. The presence or absence of ethnic minority faculty and students in our universities was and continues to be one of many indices by which we measure the willingness of this society to live up to its responsibility and promise to guarantee expanding educational opportunity for all. The creation of ethnic studies programs as a legitimate academic course of study in the university was one key part of that long range objective. Many universities now boast of departments and programs in Afro-American Studies, Puerto Rican Studies, Chicano Studies, Native American Studies, and other ethnic studies entities. Today\u27s student can leaf through the semester\u27s schedule of courses and choose from a wide array of ethnic studies offerings and think only of whether or not it fits into his/her program. Even traditional academic departments, formerly resolute in their refusal to include ethnic studies courses in their curriculum, now cross-list, and in many instances generate their own version of ethnic studies courses in direct competition with existing ethnic studies programs
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