On-line planning and scheduling: an application to controlling modular printers

We present a case study of artificial intelligence techniques applied to the control of production printing equipment. Like many other real-world applications, this complex domain requires high-speed autonomous decision-making and robust continual operation. To our knowledge, this work represents the first successful industrial application of embedded domain-independent temporal planning. Our system handles execution failures and multi-objective preferences. At its heart is an on-line algorithm that combines techniques from state-space planning and partial-order scheduling. We suggest that this general architecture may prove useful in other applications as more intelligent systems operate in continual, on-line settings. Our system has been used to drive several commercial prototypes and has enabled a new product architecture for our industrial partner. When compared with state-of-the-art off-line planners, our system is hundreds of times faster and often finds better plans. Our experience demonstrates that domain-independent AI planning based on heuristic search can flexibly handle time, resources, replanning, and multiple objectives in a high-speed practical application without requiring hand-coded control knowledge

Roadmap on dynamics of molecules and clusters in the gas phase

This roadmap article highlights recent advances, challenges and future prospects in studies of the dynamics of molecules and clusters in the gas phase. It comprises nineteen contributions by scientists with leading expertise in complementary experimental and theoretical techniques to probe the dynamics on timescales spanning twenty order of magnitudes, from attoseconds to minutes and beyond, and for systems ranging in complexity from the smallest (diatomic) molecules to clusters and nanoparticles. Combining some of these techniques opens up new avenues to unravel hitherto unexplored reaction pathways and mechanisms, and to establish their significance in, e.g. radiotherapy and radiation damage on the nanoscale, astrophysics, astrochemistry and atmospheric science

Constraint-based Scheduling

Constraint-based scheduling has become the dominant form of modeling and solving scheduling problems. Recently, due to ever more powerful embedded processors, it has become possible to embed and run constraint-based schedulers on-line even for fast processes such as product assembly sequencing. This makes constraint-based scheduling interesting to the control community as a new tool for system control, distributed and reconfigurable control, and the integration of various planning, scheduling, and control tasks. This tutorial gives a brief introduction to constraint-based scheduling, generic constraint programming techniques for modeling and solving scheduling problems, and a concrete real-time application example

Schema-Based Transformations of Logic Programs

ion Selection Specialization P1/A1 Pn/An S1/G 1 Sn/G n S/G P/A 8 Abstraction For each program P i (i=1, ... , n) we identify a program schema S i which describes P i abstractly. This abstraction generates a set of substitutions q i for schema variables. The same abstraction leads from the literals A i to the abstract literals G i . In short, the abstraction step replaces each term P i /A i by its abstraction S i /G i , and we have P i /A i = S i q i /G i q i . Selection Transformation schemata transform the set of abstract terms {S 1 /G 1 , ... , S n /G n } into an abstract term S/G, i.e. a transformation schema is defined as {S 1 /G 1 , ... , S n /G n, S/G}. In general there are several transformation schemata which have {S 1 /G 1 , ... , S n /G n } as input. We select the transformation schema which generates a desired output program schema S together with an abstract literal G. Specialization We apply the substitution q = q 1 ... q n to S/G to get the transformed pr..

rectification and constraint-based matching.

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Software Development Based on Executable Specifications and Transformations

external representations of specifications are mapped to the internal representation and only now have to spell out details that were implicit before. On the other side, components can hide implementation details, thus facilitating portability. . Components of the repository can provide default behaviour which allows us, for example, the execution of skeletal or partially incomplete specifications. . Finally, sets of interconnected components of the repository can built a framework for a problem domain, they can be considered as a theory for this domain. The common internal representation of specifications and the repository have been presented as two separate items. This need not be the case. In fact, we will introduce specification frameworks that play both roles. 4 A First Prototype: The Explore Method 4.1 Overview A first prototypical attempt to design a software development method fulfilling our requirements is restricted to executable specifications. The method, Explore, pr..

Handling

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