390 research outputs found
The Power of Modeling - a Response to PDDL2.1
In this commentary I argue that although PDDL is a very useful standard for
the planning competition, its design does not properly consider the issue of
domain modeling. Hence, I would not advocate its use in specifying planning
domains outside of the context of the planning competition. Rather, the field
needs to explore different approaches and grapple more directly with the
problem of effectively modeling and utilizing all of the diverse pieces of
knowledge we typically have about planning domains
Reformulation in planning
Reformulation of a problem is intended to make the problem more amenable to efficient solution. This is equally true in the special case of reformulating a planning problem. This paper considers various ways in which reformulation can be exploited in planning
A Neutrosophic Description Logic
Description Logics (DLs) are appropriate, widely used, logics for managing
structured knowledge. They allow reasoning about individuals and concepts, i.e.
set of individuals with common properties. Typically, DLs are limited to
dealing with crisp, well defined concepts. That is, concepts for which the
problem whether an individual is an instance of it is yes/no question. More
often than not, the concepts encountered in the real world do not have a
precisely defined criteria of membership: we may say that an individual is an
instance of a concept only to a certain degree, depending on the individual's
properties. The DLs that deal with such fuzzy concepts are called fuzzy DLs. In
order to deal with fuzzy, incomplete, indeterminate and inconsistent concepts,
we need to extend the fuzzy DLs, combining the neutrosophic logic with a
classical DL. In particular, concepts become neutrosophic (here neutrosophic
means fuzzy, incomplete, indeterminate, and inconsistent), thus reasoning about
neutrosophic concepts is supported. We'll define its syntax, its semantics, and
describe its properties.Comment: 18 pages. Presented at the IEEE International Conference on Granular
Computing, Georgia State University, Atlanta, USA, May 200
Electron transfer driven decomposition of adenine and selected analogs as probed by experimental and theoretical methods
We report on a combined experimental and theoretical study of electron transfer induced decomposition of adenine and a selection of analogue molecules in collisions with potassium atoms (K). Time-of-flight negative ion mass spectra have been obtained in a wide collision energy range (6–68 eV in the centre-of-mass frame), providing a comprehensive investigation of the fragmentation patterns of purine, adenine, 9-methyl adenine, 6-dimethyl adenine and 2-D adenine. Following our recent communication about selective hydrogen loss from the transient negative ions (TNI) produced in these collisions [T. Dunha et al. J. Chem. Phys. 148, 021101 (2018)], this work focuses on the production of smaller fragment anions. In the low-energy part of the present range, several dissociation channels that are accessible in free electron attachment experiments are absent from the present mass spectra, notably NH2 loss from adenine and 9-methyl adenine. This can be understood in terms of a relatively long transit time of the K+ cation in the vicinity of the TNI tending to enhance the likelihood of intramolecular electron transfer. In this case, the excess energy can be redistributed through the available degrees of freedom inhibiting fragmentation pathways. Ab initio theoretical calculations were performed for 9-methyl adenine (9-mAd) and adenine (Ad) in the presence of a potassium atom and provided a strong basis for the assignment the lowest unoccupied molecular orbitals accessed in the collision process
A lower bound on CNF encodings of the at-most-one constraint
Constraint "at most one" is a basic cardinality constraint which requires
that at most one of its boolean inputs is set to . This constraint is
widely used when translating a problem into a conjunctive normal form (CNF) and
we investigate its CNF encodings suitable for this purpose. An encoding differs
from a CNF representation of a function in that it can use auxiliary variables.
We are especially interested in propagation complete encodings which have the
property that unit propagation is strong enough to enforce consistency on input
variables. We show a lower bound on the number of clauses in any propagation
complete encoding of the "at most one" constraint. The lower bound almost
matches the size of the best known encodings. We also study an important case
of 2-CNF encodings where we show a slightly better lower bound. The lower bound
holds also for a related "exactly one" constraint.Comment: 38 pages, version 3 is significantly reorganized in order to improve
readabilit
The role of the agent's outside options in principal-agent relationships
We consider a principal-agent model of adverse selection where, in order to trade with the principal,
the agent must undertake a relationship-specific investment which affects his outside option to trade,
i.e. the payoff that he can obtain by trading with an alternative principal. This creates a distinction
between the agent’s ex ante (before investment) and ex post (after investment) outside options to trade.
We investigate the consequences of this distinction, and show that whenever an agent’s ex ante and ex
post outside options differ, this may equip the principal with an additional tool for screening among
different agent types, by randomizing over the probability with which trade occurs once the agent
has undertaken the investment. In turn, this may enhance the efficiency of the optimal second-best
contract
Potassium-uracil/thymine ring cleavage enhancement as studied in electron transfer experiments and theoretical calculations
We report experimental and theoretical studies on ring cleavage enhancement in collisions of potassium atoms with uracil/thymine in order to further increase the understanding of the complex mechanisms yielding such fragmentation pathways. In these electron transfer processes time-of-flight (TOF) negative ion mass spectra were obtained in the collision energy range 13.5 – 23.0 eV. We note that CNO– is the major ring breaking anion formed and its threshold formation is discussed within the collision energy range studied. Such decomposition process is supported by the first theoretical calculations in order to clarify how DNA/RNA pyrimidine bases fragmentation is enhanced in electron transfer processes yielding ion-pair formation
Efficient and Generalized Decentralized Monitoring of Regular Languages
Part 2: Monitoring and TestingInternational audienceThis paper proposes an efficient and generalized decentralized monitoring algorithm allowing to detect satisfaction or violation of any regular specification by local monitors alone in a system without central observation point. Our algorithm does not assume any form of synchronization between system events and communication of monitors, uses state machines as underlying mechanism for efficiency, and tries to keep the number and size of messages exchanged between monitors to a minimum. We provide a full implementation of the algorithm with an open-source benchmark to evaluate its efficiency in terms of number, size of exchanged messages, and delay induced by communication between monitors. Experimental results demonstrate the effectiveness of our algorithm which outperforms the previous most general one along several (new) monitoring metrics
On QBF Proofs and Preprocessing
QBFs (quantified boolean formulas), which are a superset of propositional
formulas, provide a canonical representation for PSPACE problems. To overcome
the inherent complexity of QBF, significant effort has been invested in
developing QBF solvers as well as the underlying proof systems. At the same
time, formula preprocessing is crucial for the application of QBF solvers. This
paper focuses on a missing link in currently-available technology: How to
obtain a certificate (e.g. proof) for a formula that had been preprocessed
before it was given to a solver? The paper targets a suite of commonly-used
preprocessing techniques and shows how to reconstruct certificates for them. On
the negative side, the paper discusses certain limitations of the
currently-used proof systems in the light of preprocessing. The presented
techniques were implemented and evaluated in the state-of-the-art QBF
preprocessor bloqqer.Comment: LPAR 201
Data-Oriented Declarative Language for Optimizing Business Processes
There is a signifi cant number of declarative languages to describe business
processes. They tend to be used when business processes need to be fl exible and
adaptable, being not possible to use an imperative description. Declarative languages
in business process have been traditionally used to describe the order of
activities, specifi cally the order allowed or prohibited. Unfortunately, none of them
is worried about a declarative description of exchanged data between the activities
and how they can infl uence the model. In this paper, we analyse the data description
capacity of a variety of declarative languages in business processes. Using this
analysis, we have detected the necessity to include data exchanged aspects in the
declarative descriptions. In order to solve the gap, we propose a Data-Oriented
Optimization Declarative LanguagE, called DOODLE, which includes the process
requirements referred to data description, and the possibility to include an optimization
function about the process output data
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