Korf's Conjecture and the Future of Abstraction-Based Heuristics
نویسنده
چکیده
In his 1997 paper on solving Rubik’s Cube optimally using IDA* and pattern database heuristics (PDBs), Rich Korf conjectured that there was an inverse relationship between the size of a PDB and the amount of time required for IDA* to solve a problem instance on average. In the current paper, I examine the implications of this relationship, in particular how it limits the ability of abstraction-based heuristic methods, such as PDBs, to scale to larger problems. My overall conclusion is that abstraction will play an important, but auxiliary role in heuristic search systems of the future, in contrast to the primary role it played in Korf’s Rubik’s Cube work and
منابع مشابه
A Space - Time Tradeo for A *
A memory-based heuristic is a function, h(s), stored in the form of a lookup table (pattern database): h(s) is computed by mapping s to an index and then retrieving the appropriate entry in the table. (Korf 1997) conjectures that for A* search using memory-based heuristics m t is a constant, where m is the size of the heuristic's lookup table and t is search time. In this paper we present a met...
متن کاملA Space-Time Tradeo for Memory-Based Heuristics
A memory-based heuristic is a function, h(s), stored in the form of a lookup table (pattern database): h(s) is computed by mapping s to an index and then retrieving the appropriate entry in the table. (Korf 1997) conjectures for search using memory-based heuristics that m t is a constant, where m is the size of the heuristic's lookup table and t is search time. In this paper we present a method...
متن کاملA note on Fouquet-Vanherpe’s question and Fulkerson conjecture
The excessive index of a bridgeless cubic graph $G$ is the least integer $k$, such that $G$ can be covered by $k$ perfect matchings. An equivalent form of Fulkerson conjecture (due to Berge) is that every bridgeless cubic graph has excessive index at most five. Clearly, Petersen graph is a cyclically 4-edge-connected snark with excessive index at least 5, so Fouquet and Vanherpe as...
متن کاملVideo Abstraction in H.264/AVC Compressed Domain
Video abstraction allows searching, browsing and evaluating videos only by accessing the useful contents. Most of the studies are using pixel domain, which requires the decoding process and needs more time and process consuming than compressed domain video abstraction. In this paper, we present a new video abstraction method in H.264/AVC compressed domain, AVAIF. The method is based on the norm...
متن کاملDiverse and Additive Cartesian Abstraction Heuristic
We have recently shown how counterexample-guided abstraction refinement can be used to derive informative Cartesian abstraction heuristics for optimal classical planning. In this work we introduce two methods for producing diverse sets of heuristics within this framework, one based on goal facts, the other based on landmarks. In order to sum the heuristic estimates admissibly we present a novel...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2013