| 1. |
- Ansotegui, Carlos, et al.
(author)
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Structure features for SAT instances classification
- 2017
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In: Journal of Applied Logic. - : Elsevier. - 1570-8683 .- 1570-8691. ; 23, s. 27-39
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Journal article (peer-reviewed)abstract
- The success of portfolio approaches in SAT solving relies on the observation that different SAT solvers may dramatically change their performance depending on the class of SAT instances they are trying to solve. In these approaches, a set of features of the problem is used to build a prediction model, which classifies instances into classes, and computes the fastest algorithm to solve each of them. Therefore, the set of features used to build these classifiers plays a crucial role. Traditionally, portfolio SAT solvers include features about the structure of the problem and its hardness. Recently, there have been some attempts to better characterize the structure of industrial SAT instances. In this paper, we use some structure features of industrial SAT instances to build some classifiers of industrial SAT families of instances. Namely, they are the scale-free structure, the community structure and the self similar structure. First, we measure the effectiveness of these classifiers by comparing them to other sets of SAT features commonly used in portfolio SAT solving approaches. Then, we evaluate the performance of this set of structure features when used in a real portfolio SAT solver. Finally, we analyze the relevance of these features on the analyzed classifiers.
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| 2. |
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| 3. |
- Dell'Acqua, Pierangelo, 1963-, et al.
(author)
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Common-sense reasoning as proto-scientific agent activity
- 2004
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In: Journal of Applied Logic. - : Elsevier BV. - 1570-8683 .- 1570-8691. ; 2:4, s. 385-407
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Journal article (peer-reviewed)abstract
- We wish to model common-sense reasoning in situations where it contains some of the ingredients typical of proto-scientific reasoning, with a view to future elaboration and proof of concept. To model this proto-scientific narrative, we employ the integrative formal computational machinery we have been developing and implementing for rational cooperative epistemi agents. In our logic-based framework, agents can update their own and each other's theories, which are comprised of knowledge, active rules, integrity constraints, queries, abducibles, and preferences, they can engage in abductive reasoning involving updatable preferences, set each other queries, react to circumstances, plan and carry out actions, and revise their theories and preferences by means of concurrent updates on self and others.
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| 4. |
- Dell'Acqua, Pierangelo, 1963-, et al.
(author)
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Preferential theory revision
- 2007
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In: Journal of Applied Logic. - : Elsevier BV. - 1570-8683 .- 1570-8691. ; 5:4 SPEC. ISS., s. 586-601
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Journal article (peer-reviewed)abstract
- Employing a logic program approach, this paper focuses on applying preferential reasoning to theory revision, both by means of preferences among existing theory rules, and by means of preferences on the possible abductive extensions to the theory. And, in particular, how to prefer among plausible abductive explanations justifying observations. © 2006 Elsevier B.V. All rights reserved.
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| 5. |
- Dell'Acqua, Pierangelo, 1963-, et al.
(author)
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Preferential theory revision
- 2006
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In: Journal of Applied Logic. - 1570-8683 .- 1570-8691. ; Still in Press:Available on line
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Journal article (peer-reviewed)
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| 6. |
- Eppe, Manfred, et al.
(author)
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A history based approximate epistemic action theory for efficient postdictive reasoning
- 2015
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In: Journal of Applied Logic. - : Elsevier. - 1570-8683 .- 1570-8691. ; 13:4, s. 720-769
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Journal article (peer-reviewed)abstract
- We propose an approximation of the possible worlds semantics (PWS) of knowledge with support for postdiction - a fundamental inference pattern for diagnostic reasoning and explanation tasks in a wide range of real-world applications such as cognitive robotics, visual perception for cognitive vision, ambient intelligence and smart environments. We present the formal framework, an operational semantics, and an analysis of soundness and completeness results therefrom.The advantage of our approach is that only a linear number of state-variables are required to represent an agent's knowledge state. This is achieved by modeling knowledge as the history of a single approximate state, instead of using an exponential number of possible worlds like in Kripke semantics. That is, we add a temporal dimension to the knowledge representation which facilitates efficient postdiction. Since we consider knowledge histories, we call our theory h-approximation (HPX).Due to the linear number of state variables, HPX features a comparably low computational complexity. Specifically, we show that HPX can solve the projection problem in polynomial (tractable) time. It can solve planning problems in NP, while e.g. for the action language A(k) [48] this is Sigma(P)(2)-complete. In addition to the temporal dimension of knowledge, our theory supports concurrent acting and sensing, and is in this sense more expressive than existing approximations.
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| 7. |
- Eppe, Manfred, et al.
(author)
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Approximate postdictive reasoning with answer set programming
- 2015
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In: Journal of Applied Logic. - : Elsevier. - 1570-8683 .- 1570-8691. ; 13:4, s. 676-719
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Journal article (peer-reviewed)abstract
- We present an answer set programming realization of the h-approximation (HPX) theory [8] as an efficient and provably sound reasoning method for epistemic planning and projection problems that involve postdictive reasoning. The efficiency of HPX stems from an approximate knowledge state representation that involves only a linear number of state variables, as compared to an exponential number for theories that utilize a possible-worlds based semantics. This causes a relatively low computational complexity, i.e, the planning problem is in NP under reasonable restrictions, at the cost that HPX is incomplete. In this paper, we use the implementation of HPX to investigate the incompleteness issue and present an empirical evaluation of the solvable fragment and its performance. We find that the solvable fragment of HPX is indeed reasonable and fairly large: in average about 85% of the considered projection problem instances can be solved, compared to a PWS-based approach with exponential complexity as baseline. In addition to the empirical results, we demonstrate the manner in which HPX can be applied in a real robotic control task within a smart home, where our scenario illustrates the usefulness of postdictive reasoning to achieve error-tolerance by abnormality detection in a high-level decision-making task.
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| 8. |
- Hansson, Sven Ove
(author)
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Eradication
- 2012
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In: Journal of Applied Logic. - : Elsevier BV. - 1570-8683 .- 1570-8691. ; 10:1, s. 75-84
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Journal article (peer-reviewed)abstract
- Eradication is a radical form of contraction that removes not only a sentence but also all of its non-tautological consequences from a belief set. Eradication of a single sentence that was included in the original belief set coincides with full meet contraction, but if the sentence is external to the belief set then the two operations differ. Multiple eradication, i.e. simultaneous eradication of several sentences, differs from full meet contraction even if the sentences to be contracted are all included in the original belief set. Eradication is axiomatically characterized and its properties investigated. It is shown to have close connections with the recovery postulate for multiple contraction. Based on these connections it is proposed that eradication rather than full meet contraction is the appropriate lower limiting case for multiple contraction operators.
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| 9. |
- Hansson, Sven Ove
(author)
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Semantics for more plausible deontic logics
- 2004
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In: Journal of Applied Logic. - : Elsevier BV. - 1570-8683 .- 1570-8691. ; 2, s. 3-18
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Journal article (peer-reviewed)abstract
- In order to avoid the paradoxes of standard deontic logic, we have to give up the semantic construction that identifies obligatory status with presence in all elements of a subset of the set of possible worlds. It is proposed that deontic logic should instead be based on a preference relation, according to the principle that whatever is better than something permitted is itself permitted. Close connections hold between the logical properties of a preference relation and those of the deontic logics that are derived from it in this way. The paradoxes of SDL can be avoided with this construction, but it is still an open question what type of preference relation is best suited to be used as a basis for deontic logic.
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| 10. |
- Janlert, Lars-Erik, 1950-
(author)
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Dark programming and the case for the rationality of programs
- 2008
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In: Journal of Applied Logic. - : Elsevier. - 1570-8683 .- 1570-8691. ; 6, s. 545-552
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Journal article (peer-reviewed)abstract
- Programming normally proceeds from subjective method to objective method: to program a task, you need to be able to do the task; at least “in principle.” Some new techniques of producing programs, exemplified by evolutionary algorithm techniques, do not involve any such subjective method. Is this still programming, and are the results really programs? To answer, the concept of program is reexamined. It is argued that in addition to being causative and descriptive, a program must also be rationally justifiable, i.e., the specific structure of the program should be explainable by the (rational) ways in which it contributes to achieving the intended goal. Whereas traditional programming is rational in the sense that it provides the program with a rationale by its reliance on subjective method and problem solving, these new techniques of “dark programming” do not produce any rationale; moreover, the results are not restricted to be easily rationalized. Dark programs are not guaranteed to be proper programs, but dark programming can still be used as a tool in proper (rational) programming. The business of programming then takes a turn from problem solving in the sense of invention and engineering towards problem solving in the sense of explanation and research.
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