N.N.

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N.N.,
an experimental chess system to select reasonable moves in quiet middlegame positions, developed by Bernd Owsnicki and Kai von Luck at University of Hamburg, written in LISP as subject of their Ph.D. theses ¹, further introduced 1984 at the Advances in Computer Chess 4 conference ². N.N. is based on hierarchically structured chess knowledge, conceptional divided into three main components, the knowledge bases, the planning system, and various dynamic data structures. The knowledge bases represent positional knowledge and associate classes of pawn structure with plans and actions. The planning system directs the evaluation of plans. Each plan is associated with some specific formation and has to be verified dynamically in a concept tree in order to overcome problems resulting from erroneous assumptions about the character of the position. At the conference, two distinct areas of planning were demonstrated, minority attack and the elementary endgame KPK ³. Three typical areas of possible errors were mentioned - each with its own cause and each with a different level of solvability ⁴, errors in a particular knowledge base, errors from design decisions, typically about the interaction of distinct instances in the concept tree, and errors in the semantic of planning.

N.N.

Alexander Reinefeld (1985). Kai von Luck: Aspekte wissensgestützter Planung. Bernd Owsnicki: Repräsentation von positionellem Schachwissen mit Techniken der künstlichen Intelligenz. ICCA Journal, Vol. 8, No. 4 ↩︎
Bernd Owsnicki, Kai von Luck (1986). N.N.: A Case Study in Chess Knowledge Representation. Advances in Computer Chess 4 ↩︎
Jaap van Oosterwijk Bruyn (1984). The Fourth Conference on Advances in Computer Chess. ICCA Journal, Vol. 7, No. 2 ↩︎
Dap Hartmann (1987). Book review: Advances in Computer Chess 4 from ACM Portal ↩︎

Contents

Dynamic Behavior

A sketch of N.N.'s dynamic behavior, considerably simplified ¹:

  Knowledge Bases           Processes           Knowledge Bases
 ┌────────────────┐     ╓────────────────╖     ┌────────────────┐
 │  Prototype     │     ║  Net           ║     │ Discrimination │
 │  Frames        │  ┌─►║  Interpreter   ║◄────│ Net            │
 └────────────────┘  │  ╙────────────────╜     └────────────────┘
     model           │      classes of           classification
     knowledge       │       a given             knowledge
         .           │      position
         .           │          ║
         ▼           │          ▼
 ┌────────────────┐  │  ╓────────────────╖     ┌────────────────┐
 │  Instance      │──┘  ║  Task          ║◄────│ Action         │
 │  Frames        │◄─┐  ║  Scheduler     ║  ┌──│ Scripts        │
 └────────────────┘  │  ╙────────────────╜  │  └────────────────┘
     position        │     trigger of       │     plan
     knowledge       │     appropriate      │     knowledge
                     │     scripts          │
                     │          ║           │
                     │          ▼           │
                     │  ╓────────────────╖  │  ┌────────────────┐
                     └─►║  Task          ║◄─┘  │ Concept        │
                        ║  Scheduler     ║────►│ Tree           │
                        ╙────────────────╜     └────────────────┘
                          concretization          concrete plan
                          of scripts

──► information flow

══► control flow

··► inheritance

Etymology

"N. N." is commonly used in the notation of chess games ², not only when one participant's name is genuinely unknown but when an untitled player faces a master, as in a simultaneous exhibition. Another reason is to protect a known player from the insult of a painful defeat ³ .