904 research outputs found
The Main Features of a Planner Fully Based on LTL
No full textIn this work we describe a prototype system, Padok (Planning with Domain Knowledge), where the whole planning domain is modelled in Linear Time Logic (LTL) and planning is reduced to model search. The problem specification accepted by the system can include problem specific information, in a declarative format. The work briey resumes and extends (Cialdea Mayer et al. 2000), showing, through a complete example, how LTL is effectively used as a planning language
Linear Temporal Logic as An executable semantics for planning languages
No full textThis work presents an approach to artificial intelligence planning
based on linear temporal logic (LTL). The language PDDL-K (Planning Domain Description Language with control Knowledge), a simple and easy-to-use planning language, is described. This language allows one to specify a
planning problem together with heuristic information that can be of
help for both pruning the search space and find better plans. The
semantics of the language is given in terms of a translation into a
set of LTL formulae. Planning is then reduced to ``executing'' the
LTL encoding, i.e. to model search in LTL.
The choice of LTL is due to two main reasons. First of all, it allows
a simple and natural representation of a world that changes over time.
Secondly, it is decidable. These two features together free planning
in LTL from the above mentioned
inconveniences of planning in (either propositional or
first-order) classical logic.
Moreover, domain dependent knowledge as well as
intermediate tasks can be easily expressed both in LTL
The feasibility of the
approach has been successfully tested by means of the system Pdk,
an implementation of the proposed method.
Since expressing control knowledge correctly as LTL formulae can be quite a
delicate task, Pdk has equipped by tools
supporting the domain expert in the specification task, in particular
debugging tools, and the language PDDL-K
On timeline-based games and their complexity
No full textIn timeline-based planning, domains are described as sets of independent, but interacting, components, whose behaviour over time (the set of timelines) is governed by a set of temporal constraints. A distinguishing feature of timeline-based planning systems is the ability to integrate planning with execution by synthesising control strategies for flexible plans. However, flexible plans can only represent temporal uncertainty, while more complex forms of nondeterminism are needed to deal with a wider range of real-world domains. In this paper, we propose a novel game-theoretic approach to timeline-based planning problems, generalising the state of the art while uniformly handling temporal uncertainty and nondeterminism. We define a general concept of timeline-based game and we show that the notion of winning strategy for these games is strictly more general than that of control strategy for dynamically controllable flexible plans. Moreover, we show that the problem of establishing the existence of such winning strategies is 2EXPTIME-complete
Planning under Uncertainty in Linear Time Logic
No full textThe “planning as satisfiability” approach for classical planning
establishes a correspondence between planning problems and logical
theories, and, consequently, between plans and models. This work
proposes a similar framework for contingency planning: considering contingent
planning problems where the sources of indeterminism are incomplete
knowledge about the initial state, non-inertial fluents and nondeterministic
actions, it shows how to encode such problems into Linear
Time Logic. Exploiting the semantics of the logic, and the notion of
conditioned model introduced in this work, a formal characterization is
given of the notion of contingent plan (a plan together with the set of
conditions that ensure its executability)
POLICY SPACE: WHAT, FOR WHAT, AND WHERE?
No full textThe paper examines how developing countries can use existing policy space, and enlarge it, without opting out of international commitments. It argues that: (i) a meaningful context for policy space must extend beyond trade policy and include macroeconomic and exchange-rate policies that will achieve developmental goals more effectively; (ii) policy space depends not only on international rules but also on the impact of international market conditions and policy decisions taken in other countries on the effectiveness of national policy instruments; and (iii) international integration affects policy space through several factors that pull in opposite directions; whether it increases or reduces policy space differs by country and type of integration.
Labelled Deduction
No full textPreface - D. Basin, M. D'Agostino, D. M. Gabbay, S. Matthews, L. Viganò.
Labelled Proof Systems for Intuitionistic Provability - V. Balat, D. Galmiche.
Normal Multimodal Logics with Interaction Axioms - M. Baldoni.
The SAT Problem of Signed CNF Formulas - B. Beckert, R. Hähnle, F. Manyà.
Discipline as Logic: Treating Labels as First Class Citizens - P. Blackburn.
Labelled Abduction (I) - K. Broda, D.M. Gabbay.
Labelled Tableaux for Propositional Linear Time Logic over Finite Frames - S. Cerrito, M. Cialdea Mayer.
Fibred Modal Tableaux - D.M. Gabbay, G. Governatori.
Labelled Deduction for the Guarded Fragment - M. Marx, S. Mikulás, S. Schlobach.
Semantics for Temporal Annotated Constraint Logic Programming - A. Raffaetà, T. Frühwirth.
The Logic of Reusable Propositional Output with the Fulfilment Constraint - L. van der Torre
Analysis of the Distribution of Fracture Toughness Values measured with 1T C(T) Specimens at Loading Rates higher than dK/dt=105 MPa√m s-1
No full textAbstractIn a research project investigating the correlation of dynamic crack initiation and crack arrest, funded by the German government, tests at -20 °C on specimens of 22 NiMoCr 3 7 steel (A 508 Cl.2) were performed with different specimen geometries and loading devices in the range of dK/dt=105 MPa√m s-1, Mayer (2012), Böhme et al. (2013), Mayer and Offermanns (2013). New results were obtained in the current follow-up joint IWM-MPA project in a temperature range from -20 °C to +20 °C from test series in this range of loading rates, Mayer (2015). Results from tests with 1T C(T)-specimen tested at MPA Stuttgart at loading rates higher than dK/dt=105 MPa√m s-1 are analyzed. This analysis shows the need of modifications to the standard evaluation method in ASTM E1921 if used for tests at elevated loading rates. The assumed distribution of the fracture toughness values and the form of the master curve has to be adapted and a more precise correlation of the measured reference temperature T0,X to the loading rate at fracture initiation has to be considered. Suggestions for suitable changes in the annex of ASTM E1921 for the evaluation of elevated loading rate data are presented
Metaprotella sandalensis Mayer 1898
No full textMetaprotella sandalensis Mayer, 1898 (Fig. 8) Metaprotella sandalensis Mayer, 1898: 53 –56, figs. 1–6; Mayer, 1903: 40 –42, pl. 1, figs. 30 –31, 34– 36, pl. 6, figs. 56–63, pl. 9, figs. 16 –17, 44, 60 (included f. ralumiana, singaporensis, dolichocephala, gisserana, amboinensis, typica); Müller, 1990: 836 –842, figs. 41–64. Material examined. BT: 36 males, 41 females, 21 juveniles, on Turbinaria ornata, 3 m, 9 July 2002; AB: 1 males, 3 females, 1 juvenile, on T. ornata, 2 m, 12 July 2002; IB: 4 males, 7 females, 3 juveniles, on T. ornata, 4–5 m, 18 July 2002; BB: 1 male on Jania sp., 2–3 m, 30 July 2002. Remarks. Metaprotella sandalensis has been recently redescribed in detail by Müller (1990) and the specimens from Mauritius agree with this complete redescription. This species is very common in shallow waters of the tropical IndoPacific Ocean (Müller, 1990). On Mauritius Island, M. sandalensis is also the most abundant and common species. The genus Metaprotella has been recently revised by Larsen (1997) and there are complete keys to the species of Metaprotella (Larsen, 1997; GuerraGarcía, 2002 a). A molecular approach would probably reveal the existence of cryptic species inside a complex under the name M. sandalensis. In a recent study at Lizard Island, Great Barrier Reef, Australia, the author found a great variety of morphological forms and habitats for M. sandalensis. Further genetic studies are necessary to investigate if the variation among specimens of M. sandalensis is intra or interspecific. Müller (1990) reported that M. sandalensis prefers not very exposed locations. Study of material from Australia and Papua New Guinea has revealed that the species can live in many different substrate, having been found on algae, gorgonians, soft corals, sponges, ascidians, soft bottoms, coral rubbles, sea grasses, hydroids, bryozoans and mangroves (GuerraGarcía, personal observation).Published as part of Guerra-García, José M., 2003, The Caprellidea (Crustacea: Amphipoda) from Mauritius Island, Western Indian Ocean, pp. 1-24 in Zootaxa 232 on page 15, DOI: 10.5281/zenodo.15699
- …
