2,543 research outputs found
Genetic Algorithms in Time-Dependent Environments
The influence of time-dependent fitnesses on the infinite population dynamics
of simple genetic algorithms (without crossover) is analyzed. Based on general
arguments, a schematic phase diagram is constructed that allows one to
characterize the asymptotic states in dependence on the mutation rate and the
time scale of changes. Furthermore, the notion of regular changes is raised for
which the population can be shown to converge towards a generalized
quasispecies. Based on this, error thresholds and an optimal mutation rate are
approximately calculated for a generational genetic algorithm with a moving
needle-in-the-haystack landscape. The so found phase diagram is fully
consistent with our general considerations.Comment: 24 pages, 14 figures, submitted to the 2nd EvoNet Summerschoo
A synthesis of logic and bio-inspired techniques in the design of dependable systems
Much of the development of model-based design and dependability analysis in the design of dependable systems, including software intensive systems, can be attributed to the application of advances in formal logic and its application to fault forecasting and verification of systems. In parallel, work on bio-inspired technologies has shown potential for the evolutionary design of engineering systems via automated exploration of potentially large design spaces. We have not yet seen the emergence of a design paradigm that effectively combines these two techniques, schematically founded on the two pillars of formal logic and biology, from the early stages of, and throughout, the design lifecycle. Such a design paradigm would apply these techniques synergistically and systematically to enable optimal refinement of new designs which can be driven effectively by dependability requirements. The paper sketches such a model-centric paradigm for the design of dependable systems, presented in the scope of the HiP-HOPS tool and technique, that brings these technologies together to realise their combined potential benefits. The paper begins by identifying current challenges in model-based safety assessment and then overviews the use of meta-heuristics at various stages of the design lifecycle covering topics that span from allocation of dependability requirements, through dependability analysis, to multi-objective optimisation of system architectures and maintenance schedules
Review and Comparison of Intelligent Optimization Modelling Techniques for Energy Forecasting and Condition-Based Maintenance in PV Plants
Within the field of soft computing, intelligent optimization modelling techniques include
various major techniques in artificial intelligence. These techniques pretend to generate new business
knowledge transforming sets of "raw data" into business value. One of the principal applications of
these techniques is related to the design of predictive analytics for the improvement of advanced
CBM (condition-based maintenance) strategies and energy production forecasting. These advanced
techniques can be used to transform control system data, operational data and maintenance event data
to failure diagnostic and prognostic knowledge and, ultimately, to derive expected energy generation.
One of the systems where these techniques can be applied with massive potential impact are the
legacy monitoring systems existing in solar PV energy generation plants. These systems produce a
great amount of data over time, while at the same time they demand an important e ort in order to
increase their performance through the use of more accurate predictive analytics to reduce production
losses having a direct impact on ROI. How to choose the most suitable techniques to apply is one of
the problems to address. This paper presents a review and a comparative analysis of six intelligent
optimization modelling techniques, which have been applied on a PV plant case study, using the
energy production forecast as the decision variable. The methodology proposed not only pretends
to elicit the most accurate solution but also validates the results, in comparison with the di erent
outputs for the di erent techniques
MAXIMIZATION OF ORGANIZATIONAL UPTIME USING AN INTERACTIVE GENETIC-FUZZY SCHEDULING AND SUPPORT SYSTEM
This paper addresses the problem of scheduling multiple
time and priority sensitive tasks efficiently in an environment
where the number of resources is limited and the resources
have varying capabilities and restricted capacities.
We use a help desk environment as our working model,
however, the methodologv could also be adapted to a variety
of job shop scheduling problems in general. We introduce
a metric called priority time usage as a measure of
task urgency and of schedule efficiency. We also introduce
a method of considering user satisfaction in scheduling by
utilizing fuzzy monotonic reasoning. We propose a methodology
for implementing a heuristic genetic algorithm
(GA) to accomplish the scheduling task. We discuss how
such a system can use ongoing data about historical
schedule performance to adapt and create progressively
more accurate schedules in the future. We consider
modifications to the scheduling approach which could
allow for task inter-dependencies. We present an initiative
user interface which we developed to aid help desk
administrators in using the system. In addition to providing
a front end to the SOGA system, the interface allows the
user of the system to perform "what ifâ analysis with actual
schedules. Lastly, we present preliminary assessments of
the utility of both the optimization engine and the user
interface.Information Systems Working Papers Serie
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