1,230 research outputs found
A Parametric Hierarchical Planner for Experimenting Abstraction Techniques
This paper presents a parametric system, devised
and implemented to perform hierarchical planning
by delegating the actual search to an external
planner (the "parameter") at any level of abstraction,
including the ground one. Aimed at
giving a better insight of whether or not the exploitation
of abstract spaces can be used for
solving complex planning problems, comparisons
have been made between instances of the
hierarchical planner and their non hierarchical
counterparts. To improve the significance of the
results, three different planners have been selected
and used while performing experiments.
To facilitate the setting of experimental environments,
a novel semi-automatic technique,
used to generate abstraction hierarchies starting
from ground-level domain descriptions, is also
described
A Critical Look at the Abstraction Based on Macro-Operators
Abstraction can be an effective technique for dealing with
the complexity of planning tasks. This paper is aimed at assessing and
identifying in which cases abstraction can actually speed-up the overall
search. In fact, it is well known that the impact of abstraction on the
time spent to search for a solution of a planning problem can be positive
or negative, depending on several factors -including the number of objects
defined in the domain, the branching factor, and the plan length.
Experimental results highlight the role of such aspects on the overall performance
of an algorithm that performs the search at the ground-level
only, and compares them with the ones obtained by enforcing abstraction
PACMAS: A Personalized, Adaptive, and Cooperative MultiAgent System Architecture
In this paper, a generic architecture, designed to
support the implementation of applications aimed at managing
information among different and heterogeneous sources,
is presented. Information is filtered and organized according
to personal interests explicitly stated by the user. User pro-
files are improved and refined throughout time by suitable
adaptation techniques. The overall architecture has been called
PACMAS, being a support for implementing Personalized, Adaptive,
and Cooperative MultiAgent Systems. PACMAS agents are
autonomous and flexible, and can be made personal, adaptive and
cooperative, depending on the given application. The peculiarities
of the architecture are highlighted by illustrating three relevant
case studies focused on giving a support to undergraduate and
graduate students, on predicting protein secondary structure, and
on classifying newspaper articles, respectively
Notes for an aesthetic approach to walking
Walking has been dealt with from various points of view and by various disciplines and practices, including art and aesthetics. In order to encompass such a phenomenon in an adequate way, an ad hoc terminology has been often coined. Among the terms that have been appositely created, at least four are worth mentioning: âodologyâ (John Brinckerhoff Jackson), âhodological spaceâ (Kurt Lewin, Jean-Paul Sartre and Otto Friedrich Bollnow), âstrollologyâ (Lucius and Annemarie Burckhardt), and âwalkscapesâ (Francesco Careri). However distinct and somewhat divergent these may be, the four approaches labeled with these four terms all focus their attention to the relationship between body and space, considering walking as a fundamental moment of the bodily experience of space. For this reason, they can be fruitfully put in relation with the artistic practice of the so-called âwalking artistsâ, such as Richard Long, Hamish Fulton, and Michael Höpfner, who pursue the same purposes.peer-reviewe
It's All Relative: Perceptions of (Comparative) Candidate Incivility and Candidate Sympathy in Three Multiparty Elections
While growing attention has been devoted to candidatesâ use of incivility in campaigns, its role in informing votersâ feelings toward candidates is still debated. This study embraces a constructionist perspective on incivility and focuses on the relationship between perceptions of candidate incivility and candidate sympathy. Its contribution is twofold. First, it extends incivility research generalizability by testing the association between votersâ perceptions of candidate incivility and candidate sympathy during three election campaigns beyond the US context. Second, it builds upon the notion of incivility as a norm violation and tests the hypothesis that perceptions of a candidateâs uncivil behavior are negatively associated with candidate sympathy when this behavior is inappropriate (i.e., it violates injunctive civility norms) and especially when it is uncommon (i.e., it violates descriptive civility norms). These interests are pursued through postâelectoral survey data collected in the Netherlands, Germany, and France. Findings show that incivility perceptions can, but not always, correspond to more negative feelings toward candidates. Furthermore, it is the incivility of candidates relative to that of their competitors that really counts for candidate sympathy. Supplementary Files: https://www.cogitatiopress.com/politicsandgovernance/article/downloadSuppFile/5677/279
Hans Belting and hermeneutics. Between unease and awareness
Beginning with an article by Hans Robert Jauss, which detects in Hans Belting some "unease" towards hermeneutics, this paper claims instead that Belting, in his studies, manifests deep hermeneutic awareness, among other things indebted in many respects to Jauss' reception theory itself. Nonetheless, it is still possible to notice some "unease," which emerges in the way Belting considers hermeneutics among the "methods and games" of history of art. In this regard, Belting's analysis â concerning the relationship between iconology and hermeneutics and between philosophical and art historical hermeneutics â appears densely loaded with meaning but also partial. This is due to the fact that he limits himself to critically discussing only one tendency, well represented, in his eyes, by Wilhelm Dilthey, Hans-Georg Gadamer and Hans Sedlmayr, the latter being the only representative of art historical hermeneutics that Belting takes into account
Molecular mechanism of MBX2319 inhibition of Escherichia coli AcrB multidrug efflux pump and comparison with other inhibitors
Efflux pumps of the resistance nodulation division (RND) superfamily, such as AcrB, make a major contribution to multidrug resistance in Gram-negative bacteria. The development of inhibitors of the RND pumps would improve the efficacy of current and next-generation antibiotics. To date, however, only one inhibitor has been cocrystallized with AcrB. Thus, in silico struc- ture-based analysis is essential for elucidating the interaction between other inhibitors and the efflux pumps. In this work, we used computer docking and molecular dynamics simulations to study the interaction between AcrB and the compound MBX2319, a novel pyranopyridine efflux pump inhibitor with potent activity against RND efflux pumps of Enterobacteriaceae species, as well as other known inhibitors (D13-9001, 1-[1-naphthylmethyl]-piperazine, and phenylalanylarginine-Ă-naphthyl-amide) and the binding of doxorubicin to the efflux-defective F610A variant of AcrB. We also analyzed the binding of a sub- strate, minocycline, for comparison. Our results show that MBX2319 binds very tightly to the lower part of the distal pocket in the B protomer of AcrB, strongly interacting with the phenylalanines lining the hydrophobic trap, where the hydrophobic por- tion of D13-9001 was found to bind by X-ray crystallography. Additionally, MBX2319 binds to AcrB in a manner that is similar to the way in which doxorubicin binds to the F610A variant of AcrB. In contrast, 1-(1-naphthylmethyl)-piperazine and phenylalanylarginine-Ă-naphthylamide appear to bind to somewhat different areas of the distal pocket in the B protomer of AcrB than does MBX2319. However, all inhibitors (except D13-9001) appear to distort the structure of the distal pocket, impairing the proper binding of substrates
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