2,935 research outputs found
Effect of timing and female quality on clutch size in the Collared Flycatcher Ficedula albicollis
Capsule: Laying date and female age appear to be related to clutch size.
Aims: To test two hypotheses ('date' and 'quality'), which might explain why fewer eggs are laid late in the season.
Methods: Four years of data and multivariate analysis were used to test the effects of timing of breeding and female quality reflected by morphological variables and age on clutch size in the Collared Flycatcher Ficedula albicollis. We estimated food supply during parental care by measuring diet composition of nestlings.
Results: We distinguished the independent effects of date and age of females on clutch size. The type of prey fed to nestlings was different early and late in the season. Hence food supply during the nestling care period may be a limiting environmental factor that indirectly determines clutch size.
Conclusion: Our results are consistent with the predictions of the date hypothesis, but the quality hypothesis was also partially supported. Depending on year effects, 30-50% of the variance in clutch size may be related to the timing of breeding and an additional 5-10% may be due to quality (age) differences between early- and late-breeding birds
Multi-Agent Cooperation for Particle Accelerator Control
We present practical investigations in a real industrial controls environment
for justifying theoretical DAI (Distributed Artificial Intelligence) results,
and we discuss theoretical aspects of practical investigations for
accelerator control and operation. A generalized hypothesis is introduced,
based on a unified view of control, monitoring, diagnosis, maintenance and
repair tasks leading to a general method of cooperation for expert systems
by exchanging hypotheses. This has been tested for task and result sharing
cooperation scenarios. Generalized hypotheses also allow us to treat the
repetitive diagnosis-recovery cycle as task sharing cooperation. Problems
with such a loop or even recursive calls between the different agents are
discussed
Beliefs and Conflicts in a Real World Multiagent System
In a real world multiagent system, where the
agents are faced with partial, incomplete and
intrinsically dynamic knowledge, conflicts are
inevitable. Frequently, different agents have
goals or beliefs that cannot hold simultaneously.
Conflict resolution methodologies have to be
adopted to overcome such undesirable occurrences.
In this paper we investigate the application of
distributed belief revision techniques as the support
for conflict resolution in the analysis of the
validity of the candidate beams to be produced
in the CERN particle accelerators.
This CERN multiagent system contains a higher
hierarchy agent, the Specialist agent, which
makes use of meta-knowledge (on how the conflicting
beliefs have been produced by the other
agents) in order to detect which beliefs should be
abandoned. Upon solving a conflict, the Specialist
instructs the involved agents to revise their
beliefs accordingly.
Conflicts in the problem domain are mapped into
conflicting beliefs of the distributed belief revision
system, where they can be handled by
proven formal methods. This technique builds
on well established concepts and combines them
in a new way to solve important problems. We
find this approach generally applicable in several
domains
A Rule-Based Consultant for Accelerator Beam Scheduling Used in the CERN PS Complex
The CERN PS accelerator complex consists of nine interacting accelerators which work together to produce
particle beams for different end users, varying in particle type, energy, time structure, and geometry. The beam
production schedule is time sliced and depends on the current operational requirements and dynamically on the
accelerator status, so that production schedule changes occur in real time. Many potential schedules are not valid due
to various system constraints and these constraints vary over time as new operational modes are introduced. In order
to ensure that only valid schedules are given to the complex, an automated tool has been developed to indicate
whether a potential schedule is valid or not. This presentation describes the method by which the validity of a beam
schedule is determined and how this method was implemented using a rule-based approach based on SQL, avoiding
the use of an expert system shell. Both the data to instantiate the rules and the rules themselves are kept in an Oracle
data base. The SQL interpreter provides the inference engine for this knowledge-based system. A few examples are
presented and the running experience with the tool is discussed
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