The struggle for respect in a Planning Centric World… Stephen Smith Carnegie Mellon University

AI Scheduling – the struggle for respect …  1990s – Formation of research community  The Period of Basic Disconnect  Int. Conference on AI Planning Systems (AIPS)  European Conference on Planning (ECP)  Perspectives:  There is a restricted class of planning problems concerned with synchronizing plans in time (mostly uninteresting from the standpoint of stacking blocks)  Is scheduling about core techniques or about solving application problems?

AI Scheduling – the struggle for respect …  – Recognition  AIPS changed its name to Int. Conf. on AI Planning and Scheduling  I got a paper accepted in ECP!  Perspectives  Increasing recognition that most real planning problems must worry about situating actions in time and making good use of scarce resources  Consideration of integration frameworks  But majority view of scheduling is really still as a black box component of a larger planning system

AI Scheduling – the struggle for respect …  2003 onward – Age of Acceptance (?)  Less work in the planning community on inventing planning techniques to solve scheduling problems  At ICAPS 2004, we actually held a workshop on how planning might be used to solve scheduling subproblems  More emphasis on common core technologies: temporal reasoning, search

What is Planning and Scheduling?  Planning - Synthesis of action sequences to achieve goals (what to do)  Scheduling - Assignment of resources and times to actions to maximize performance (how and when) OP 1,1 OP 1,2 OP 1,3 OP 2,1 OP 2,2 R1 R2 rd 1 dd 1 dd 2 rd 2 st(i) + p(i) ≤ st(j), where p(i) is the processing time of op i st(i) + p(i) ≤ st(j) ∨ st(j) + p(j) ≤ st(i) rd(j) ≤ st(i) for each op i of job j Minimize ∑ |c(j) - dd(j)| ij R i j on(b,t) on(g,t) on(r,g) on(b,r) on(g,r) clear(b) clear(r) stack(b,r) stack(g,b) putdown(r) clear(g) clear(x) clear(y) on(x,?) preconds ¬on(x,?) on(x,y) clear(?) postconds stack(x,y) clear(x) on(x,?) preconds ¬on(x,?) on(x,t) postconds clear(?) putdown(x) Planning Scheduling durative actions, temporal reasoning maximizing # of goals achieved, # of soft constraints satisfied resources action selection from pre-computed resource & process alternatives resource setup and state constraints In recent years, the distinction has started to blur: OP 1,1 OP 2,2 OP 1,3 OP 1,2 R2 R1 OP 2,1