## Comparing subsumption optimizations (1998)

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Venue: | Collected Papers from the International Description Logics Workshop (DL'98 |

Citations: | 21 - 12 self |

### BibTeX

@INPROCEEDINGS{Horrocks98comparingsubsumption,

author = {Ian Horrocks and Peter F. Patel-schneider},

title = {Comparing subsumption optimizations},

booktitle = {Collected Papers from the International Description Logics Workshop (DL'98},

year = {1998},

pages = {90--94}

}

### Years of Citing Articles

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### Abstract

Effective systems for expressive description logics require a heavily-optimised subsumption checker incorporating a range of optimisation techniques. Because of the correspondence between description logics and propositional modal logic most of these techniques carry over into propositional modal logic satisfiability checking. Some of the techniques are extremely effective on various test suites for propositional modal satisfiability and others are less effective. Further, the effectiveness of a technique depends on the test performed. Description logic systems spend much of their time computing subsumption relationships between descriptions. If the system is based on an expressive description logic then the

### Citations

168 | Improvements to propositional satisfiability search algorithms
- Freeman
- 1995
(Show Context)
Citation Context ...e the search by selecting the next disjunct on which to branch. These heuristics typically try to maximise the effectiveness of BCP by selecting disjuncts which occur frequently in small disjunctions =-=[5]-=-. However, these techniques do not work well with modal problems because they rely for their effectiveness on finding the same disjuncts recurring in multiple disjunctions. This is likely in non-modal... |

121 |
Optimising Tableaux Decision Procedures for Description Logics
- Horrocks
- 1997
(Show Context)
Citation Context ... performing subsumption checks, and they also optimise the subsumption check itself. Two other systems that explore the optimisations required to build an expressive description logic system are FaCT =-=[9]-=-, a full description logic system, and DLP [12], an experimental system providing only a limited description logic interface. The subsumption checkers for both FaCT and DLP incorporate a range of know... |

118 |
Solving Propositional Satisfiability Problems
- Jeroslow, Wang
- 1990
(Show Context)
Citation Context ...ckjumping. This is done by branching first on a disjunction with the oldest dependencies [9]. The disjunct within these disjunctions is chosen using Jeroslow and Wang’s weighted occurrences heuristic =-=[11]-=- (the JW heuristic hereafter), a BCP-maximising heuristic. In addition, DLP reduces the size of the search space by using similar heuristic techniques to select the order in whichR-successors of a nod... |

66 |
Probabilistic analysis of the Davis–Putnam procedure for solving the satisfiability problem
- Franco, Paull
- 1983
(Show Context)
Citation Context ...tic is designed for non-modal problems whereas the oldestfirst heuristic enhances backjumping. Our second propositional modal logic test suite uses a common method for testing SAT decision procedures =-=[4]-=- that has been adapted for use with propositional modalKby Giunchiglia and Sebastiani [7], and further refined by Hustadt and Schmidt [10]. The method uses a random generator to produce formulae, with... |

56 | A SAT-based Decision Procedure for ALC
- Giunchiglia, Sebastiani
- 1996
(Show Context)
Citation Context ...scription logic subsumption problems! FaCT and DLP implement a superset of the propositional modal logic K4 (m). A number of testing methodologies have been established for propositional modal logics =-=[8, 7, 10]-=- and we have used these to perform experiments comparing the effectiveness of the various optimisations built into FaCT and DLP. 1 The Description Logic ALC R + Both FaCT and DLP implement a superset ... |

54 | On Evaluating Decision Procedures for Modal Logics
- Hustadt, Schmidt
- 1997
(Show Context)
Citation Context ...description logic subsumption problems! FaCT and DLP implement a superset of the propositional modal logicK4(m). A number of testing methodologies have been established for propositional modal logics =-=[8; 7; 10]-=- and we have used these to perform experiments comparing the effectiveness of the various optimisations built into FaCT and DLP. Aj>j?j The Description Both FaCT and DLP implement a superset ofALCR+, ... |

52 | Intelligent Backtracking on Constraint Satisfaction Problems: Experimental and Theoretical Results
- Baker
- 1995
(Show Context)
Citation Context ...acking search known as thrashing. DLP tackles this problem by adapting a form of dependency directed backtracking called backjumping, which has been used in solving constraint satisfiability problems =-=[2]-=-. Backjumping labels concept expressions with a dependency set indicating the branch points on which they depend. When a clash is discovered, the dependency sets can be used to identify the most recen... |

52 | Implementing and testing expressive description logics: Preliminary report
- Bresciani, Franconi, et al.
- 1995
(Show Context)
Citation Context ...s—with an expressive description logic, the time taken by a small number of hard subsumption checks can dominate the total time. Two systems based on expressive description logics, KRIS [1] and CRACK =-=[3]-=-, have incorporated a number of optimisations to achieve better performance of their subsumption checkers. These systems use various techniques to avoid performing subsumption checks, and they also op... |

52 | Experience building a large, re-usable medical ontology using a description logic with transitivity and concept inclusions
- Rector, Horrocks
- 1997
(Show Context)
Citation Context ...es make a dramatic difference to the performance of the overall system. As evidence, KRIS is not able to load (a modified version of) a large medical terminology knowledge base from the GALEN project =-=[13]-=- because it gets stuck trying to perform one of the thousands of required subsumption tests. FaCT and DLP, which have higher levels of optimisation, are able to easily load this Peter F. Patel-Schneid... |

50 | A concept language extended with different kinds of transitive roles
- Sattler
(Show Context)
Citation Context ...l for the initial concept. If the algorithm fails to construct such a collection then the initial concept is unsatisfiable. The details of the basic algorithm are fairly standard, and can be found in =-=[14]-=-. Optimisation Techniques A naive implementation of the tableaux method would be much too slow to be used for subsumption testing in a description logic. DLP (and FaCT) 2 into:(8R::C) therefore employ... |

44 | A benchmark method for the propositional modal logics K, KT, S4
- Balsiger, Heuerding, et al.
- 2000
(Show Context)
Citation Context ...description logic subsumption problems! FaCT and DLP implement a superset of the propositional modal logicK4(m). A number of testing methodologies have been established for propositional modal logics =-=[8; 7; 10]-=- and we have used these to perform experiments comparing the effectiveness of the various optimisations built into FaCT and DLP. Aj>j?j The Description Both FaCT and DLP implement a superset ofALCR+, ... |

36 |
Knowledge Representation and Inference System
- KRIS
- 1991
(Show Context)
Citation Context ...sumption checks—with an expressive description logic, the time taken by a small number of hard subsumption checks can dominate the total time. Two systems based on expressive description logics, KRIS =-=[1]-=- and CRACK [3], have incorporated a number of optimisations to achieve better performance of their subsumption checkers. These systems use various techniques to avoid performing subsumption checks, an... |

17 |
Random 3-SAT Problems and the Davis-Putnam Procedure
- Hard
- 1996
(Show Context)
Citation Context ...d to try to minimise the size of the search tree. Boolean constraint propagation (BCP) is a technique used to maximise deterministic expansion, and thus pruning of the search tree via clash detection =-=[6]-=-. Before semantic branching is applied to the label of a nodex, BCP deterministically expands disjunctions inL(x)which present only rule:C;CtD D BCP uses the inference to one expansion possibility and... |

7 |
System description: DLP
- Patel-Schneider
- 1997
(Show Context)
Citation Context ...optimise the subsumption check itself. Two other systems that explore the optimisations required to build an expressive description logic system are FaCT [9], a full description logic system, and DLP =-=[12]-=-, an experimental system providing only a limited description logic interface. The subsumption checkers for both FaCT and DLP incorporate a range of known, adapted and novel optimisation techniques in... |

3 |
A SAT-based decision procedure forALC
- Giunchiglia, Sebastiani
- 1996
(Show Context)
Citation Context ...description logic subsumption problems! FaCT and DLP implement a superset of the propositional modal logicK4(m). A number of testing methodologies have been established for propositional modal logics =-=[8; 7; 10]-=- and we have used these to perform experiments comparing the effectiveness of the various optimisations built into FaCT and DLP. Aj>j?j The Description Both FaCT and DLP implement a superset ofALCR+, ... |