Object-centred planning: lifting classical planning from the literal level to the object level

McCluskey, T.L.; Kitchin, Diane E.; Porteous, Julie

doi:10.1109/tai.1996.560475

Cited by 3 publications

(4 citation statements)

References 14 publications

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“…An approach that is based on a well-founded semantic concept is that of object centered planning [183]. The corresponding Object Centered Language formalizes plan generation in terms of object oriented concepts and basically grounds operator definitions in state transitions of the involved objects.…”

Section: Planning By Action Abstractionmentioning

confidence: 99%

Hybrid Planning and Scheduling

Schattenberg¹

2015

Künstl Intell

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PrefacePlanning and scheduling are well-established disciplines in the field of Artificial Intelligence. They provide flexibility, robustness, and effectiveness to complex software systems in a variety of application areas. While planning is the process of finding a course of action that achieves a goal or performs a specified task, scheduling deals with the assignment of resources and time to given activities, taking into account resource restrictions and temporal dependencies. In other words, planning focuses on reasoning about causal structures and identifying the necessary actions for achieving a specific goal; scheduling concentrates on resource consumption and production for optimizing a coherent parameter assignment of a plan. As successful these techniques clearly are, the actual demands of complex, real-world applications go far beyond the potential of these single methods, however. They require an adequate integration of these problem solving methods as well as a combination of different planning and scheduling paradigms. Particularly important are abstraction-based, hierarchical approaches because of both their expressive knowledge representation and their efficiency in finding solutions. Current state-of-the-art systems rarely address the question of method integration; isolated approaches do so only in ad hoc implementations and mostly lack a proper formal basis.This thesis presents a formal framework for plan and schedule generation based on a well-founded conceptualization of refinement planning: An abstract problem specification is transformed stepwise into a concrete, executable solution. In each refinement step, plan deficiencies identify faulty or under-developed parts of the plan, which in turn triggers the generation of transformation operators that try to resolve them. All involved entities are explicitly represented and therefore transparent to the framework. This property allows for two novel aspects of our approach: First, any planning and scheduling methodology can be functionally decomposed and mapped on the deficiency announcement and plan transformation generation principle, and second, the framework allows for an explicit declaration of planning strategies. We first investigate the flexibility of the extremely modular system design by instantiating the framework in a variety of system configurations including classical partial-order causal-link (POCL) planning, hierarchical task-network (HTN) planning, and classical scheduling.As a key feature, the presented approach provides a formally integrated treatment of action and state abstraction, thus naturally combining causality-focused reasoning with hierarchical, procedure-oriented methods. While the use of procedural knowledge allows to rely on well-known, predefined solutions to planning problems, the non-hierarchical methods provide the flexibility to come up with non-standard solutions and to complete under-specified problem instances, respectively. The resulting technique of hybrid planning is capable of constructing a plan's caus...

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Section: Planning By Action Abstractionmentioning

confidence: 99%

Hybrid Planning and Scheduling

Schattenberg¹

2015

Künstl Intell

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“…A method for formulating domain definitions based on the object-centric idea was introduced by McCluskey et al (1996);McCluskey & Porteous, (1997), and was linked to the development of the definition language OCL, later refined into OCL h (McCluskey & Kitchin, 1998). The objectcentric approach has its roots in OCL but is capable of being lifted above the particular language that the definition is encoded in.…”

Section: Introductionmentioning

confidence: 99%

Planning domain definition using GIPO

Simpson

Kitchin

McCluskey

2007

The Knowledge Engineering Review

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In this paper an object-centric perspective on planning domain definition is presented along with an overview of GIPO (graphical interface for planning with objects), a supporting tools environment. It is argued that the object-centric view assists the domain developer in conceptualizing the domain's structure, and we show how GIPO enables the developer to capture that conceptualization at an appropriate and matching conceptual level. GIPO is an experimental environment which provides a platform for exploring and demonstrating the range and scope of tools required to support the knowledge engineering aspects of creating and validating planning systems, both for classical pre-condition planning and hierarchical planning. GIPO embodies the objectcentric view, leading to a range of benefits typically associated with object-oriented methods in other fields of software engineering such as highly visual development methods, code reuse and efficient, reliable development.

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“…Our object-centred approach to designing domain models for input to precondition planning (as detailed in [12]) has been extended to HTN models as described, with a similar range of tools which support consistency and cross checking, as well as the implementation of a tool which helps check transparency. Models are engineered in two parts, firstly in a bottom-up fashion to construct the dynamic sort hierarchy.…”

Section: S W £ 8 Smentioning

confidence: 99%

“…In this paper we extend the method and language detailed in [11] to HTN planning models, and introduce new notation and a central new domain property, to support it. In sections 2 and 3 we describe the object-centred language OCL, a hierarchical version of that used in [12], and how it can be extended naturally to OCL h to encode models for HTN planners. In section 4 we use the framework developed in section 3 to define what we call the 'model transparency property', a property which holds in a model if the main methods (the abstract operators) are structured in a coherent manner.…”

Section: Introductionmentioning

confidence: 99%

A tool-supported approach to engineering HTN planning models

McCluskey

Kitchin²

Proceedings Tenth IEEE International Conference on Tools With Artificial Intelligence (Cat. No.98CH36294)

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Our research concerns formal, expressive, objectcentred languages and tools for use in engineering domains for planning applications. In this paper we extend our recent work on an object-centred language for encoding precondition planning domains to a language called OCL h , designed for HTN planning. Domain encodings for HTN planners are particularly troublesome, because they tend to be used in knowledged-based applications requiring a great deal of 'domain engineering', and the abstract operators central to an HTN model do not share the fairly clear declarative semantics of concrete pre-and post condition operators. Central to our approach is the development, in parallel, of the abstract operator set and the hierarchical state specification of the objects that the operators manipulate. In this paper we define and illustrate a transparency property, together with a transparency checking tool, which helps the developer to encode a clear planning model in OCL h . Our encoding of the Translog domain is used as an extended example to illustrate the approach. sorts¨physical obj© v ehicle© package© crane© plane ramp sorts¨vehicle© l and carrier© airplane© train sorts¨land carrier© m ail© flatbed© regular© tanker

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Object-centred planning: lifting classical planning from the literal level to the object level

Cited by 3 publications

References 14 publications

Hybrid Planning and Scheduling

Hybrid Planning and Scheduling

Planning domain definition using GIPO

A tool-supported approach to engineering HTN planning models

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