Thesis Abstract (2016) is available at https://web.iem.technion.ac.il/en/research/seminars/eventdetail/34081/-/deterministic-oversubscription-action-planning-with-general-utility-functions.html
Abstract:
In deterministic oversubscription planning (OSP) the objective is to achieve an as valuable as possible subset of goals within a fixed allowance of the total action cost. In contrast to classical planning setup in which the objective is to achieve one of the equally attractive goal states at as low total action cost as possible, algorithmic progress in OSP has been rather slow. Recently, Mirkis and Domshlak (2014) investigated approximation techniques aiming at improving the scalability of OSP solvers, showing how standard goal-reachability landmarks of certain classical planning tasks can be compiled into an OSP task of interest, resulting in an equivalent OSP task with a lower cost allowance, and thus with a smaller search space. Based on this observation they introduced an effective framework for exploiting such landmarks in heuristic-search OSP.
The major limitation of the techniques developed by Mirkis and Domshlak was the restriction to only non-negative utility functions. In this work, we extend the scope of the landmark-based approximations to OSP problems with general utility functions and improve the scalability of the state-space search driven by these approximations. In particular, we define the notion of ‘net utility of an action’ which allows us to alleviate the dependence on value non-negativity, as well as captures relationships between state variables and different value assignments to a variable in successive states in a plan. Focusing on the net utility of action we propose a novel framework for exploiting goal-reachability landmarks in problems with general utility functions, addressing both coverage and scalability aspects of heuristic-search OSP.
Our empirical evaluation shows that our approach allows for substantial reductions in search effort in problems with general utility functions, confirms the effectiveness of the proposed techniques in the private case of OSP problem with non-negative rewards as well, and opens a wide gate for further developments in oversubscription planning.
Recent progress in Oversubscription planning available at https://mullerd.webgr.technion.ac.il/osp-publications/
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Deterministic Oversubscription Action Planning with General Utility Functions - seminar slides 2016
1. Overview From Private to General Case Empirical Evaluation Future Work
The General Case of Deterministic
Oversubscription Action Planning
Daniel Muller
Advisor: Prof. Carmel Domshlak
Faculty of Industrial Engineering and Management
Technion - Israel Institute of Technology
mullerdm@gmail.com
December 25, 2016
2. Overview From Private to General Case Empirical Evaluation Future Work
Classical Planning Problem
A problem of finding trajectories in large-scale yet concisely
represented state-transition systems
INIT Goal
Objective
Find a sequence of actions achieving goal state at minimal cost
3. Overview From Private to General Case Empirical Evaluation Future Work
Over-subscription (OSP) Planning Problem
A problem of finding trajectories in large-scale yet concisely
represented state-transition systems
INIT
Budget = 5
u( )=1
u( )=2
u( )= -3
OSP
Goal
U=4
U = 2
U = 7
U = 8
u( )=0
u( )= -1
U = -1
Objective
Find a sequence of actions to the most valuable state, within a
limited cost budget
4. Overview From Private to General Case Empirical Evaluation Future Work
Model-oriented problem solving
Planner (Solver) Plan (Solution)LanguageProblem
Problem Representation
In the spirit of Mirkis & Domshlak (2014) the OSP model
compactly represented as sextuple:
state
variables
initial state
state value
function
operators
operator cost
function
Task budget
OSP Task
5. Overview From Private to General Case Empirical Evaluation Future Work
Language
state
variables
initial state
state value
function
operators
operator cost
function
Task budget
OSP Task
Planner (Solver) Plan (Solution)LanguageProblem
State Representation:
V = {v1, . . . , vn} is a finite
set state variables
Each complete assignment
to V representing a state
S = dom(v1)×· · ·×dom(vn)
dom(va) = {on(a, b),
on(a, c), on(a, d),
ontable(a), holding(a)}
6. Overview From Private to General Case Empirical Evaluation Future Work
Language
state
variables
initial state
state value
function
operators
operator cost
function
Task budget
OSP Task
Planner (Solver) Plan (Solution)LanguageProblem
Initial State Representation:
s0 ∈ S
va = ontable(a), vb = ontable(b),
ve = ontable(e), vf = on(f, b),
vd = on(d, f), vc = on(c, e),
vca = clear(a), vcd = clear(d),
vcc = clear(c), varm = armEmpty
7. Overview From Private to General Case Empirical Evaluation Future Work
Language
state
variables
initial state
state value
function
operators
operator cost
function
Task budget
OSP Task
Planner (Solver) Plan (Solution)LanguageProblem
Actions Representation:
O is a finite set of operators
represented by preconditions
and effects, which are partial
assignments to V
pre(o) = {vc = on(a, b),
vca = clear(a)}
eff(o) = {va = holding(a),
vcb = clear(b),
vca = not clear(a)}
8. Overview From Private to General Case Empirical Evaluation Future Work
Language - OSP Extensions
state
variables
initial state
state value
function
operators
operator cost
function
Task budget
OSP Task
Planner (Solver) Plan (Solution)LanguageProblem
INIT
Budget = 5
u( )=1
u( )=2
u( )= -3
OSP
Goal
U=4
U = 2
U = 7
U = 8
u( )=0
u( )= -1
U = -1
9. Overview From Private to General Case Empirical Evaluation Future Work
Recent Advances in OSP
With the advantage of 20 years of research
Classical Planning
OSP
Mirkis and Domshlak, ECAI-14, Best Paper Award
approximation techniques based on state-space abstractions
approximation technique based on logical landmarks for goal
reachability
heuristic BFBB
10. Overview From Private to General Case Empirical Evaluation Future Work
Recent Advances in OSP
INIT
Budget = 5u( )=1
u( )=2
u( )= -3
OSP
Goal
U=4U = 2
U = 7
U = 8
u( )=0
u( )= -1
This work Mirkis &
Domshlak
work
Mirkis and Domshlak, ECAI-14, Best Paper Award
approximation techniques based on state-space abstractions
approximation technique based on logical landmarks for goal
reachability
heuristic BFBB
11. Overview From Private to General Case Empirical Evaluation Future Work
Non-Negative Rewards Framework
OSP task with
Budget = b
s3
s4
s6
s7
o8 s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
U=1
U =2
U=3
U=1
12. Overview From Private to General Case Empirical Evaluation Future Work
Non-Negative Rewards Framework
Generate an auxiliary classical planning problem
s3
s4
s6
s7
o8 s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
odummy
G
odummy
odummy
Auxiliary Classical Planning Problem
OSP task with
Budget = b
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
U=1
U =2
U=3
U=1
13. Overview From Private to General Case Empirical Evaluation Future Work
Non-Negative Rewards Framework
Use off-the-shelf classical planning tool to provide a
disjunctive formula of ’what must happen’
Transform
to:
Classical Planning off-the-shelf Tool
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
odummy
G
odummy
odummy
Auxiliary Classical Planning ProblemOSP task with
Budget = b
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
U=1
U =2
U=3
U=1
14. Overview From Private to General Case Empirical Evaluation Future Work
Non-Negative Rewards Framework
Compile the acquired formula into the original OSP task to
reduce search space
OSP task with
Budget = b
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
U=1
U =2
U=3
U=1
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
odummy
G
odummy
odummy
Auxiliary Classical Planning
Problem
Transform
to:
Classical Planning
off-the-shelf Tool
Compile the
acquired formula
into the original
OSP task to
reduce search
space
OSP task with Budget =
b’ < b
s3
s4
s6
s7
o8 s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
U=1
U =2
U=3
U=1
15. Overview From Private to General Case Empirical Evaluation Future Work
Non-Negative Rewards Framework
Execute OSP solver on the reduced problem
solve reduced task
OSP task with Budget =
b’ < b
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
U=1
U =2
U=3
U=1
OSP task with
Budget = b
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
U=1
U =2
U=3
U=1
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
odummy
G
odummy
odummy
Equivalent Classical Planning
Problem
Transform
to:
Classical
Planning off-the-
shelf Tool
Compile the
acquired formula
into the original
OSP task to
reduce search
space
16. Overview From Private to General Case Empirical Evaluation Future Work
Non-Negative Rewards Framework
Learning based, closed loop of incrementally improving best
solution so far, and reducing the search space
solve reduced task
Best solution
so far
s6
If learned
new
valuable
state
Learned valuable
states DB
New
valuable
state
OSP task with Budget =
b’ < b
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
U=1
U =2
U=3
U=1
OSP task with
Budget = b
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
U=1
U =2
U=3
U=1
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
odummy
G
odummy
odummy
Transform
to:
Classical
Planning off-the-
shelf Tool
Compile the
acquired formula
into the original
OSP task to
reduce search
space
Auxiliary Classical Planning
Problem
s4
s6
o2
o5
s0
U=1
s6 sj
si
17. Overview From Private to General Case Empirical Evaluation Future Work
Alleviate the Dependence on Value Non-Negativity
Our work contribution
Best solution
so far
s6
Learned valuable
states DB
New
valuable
state
OSP task with Budget =
b’ < b
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
U=1
U =2
U=3
U=1
OSP task with
Budget = b
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
U=1
U =2
U=3
U=1
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
odummy
G
odummy
odummy
Auxiliary Classical Planning
Problem
Classical
Planning off-the-
shelf Tool
Formula adjustment to wider
range of values
Compile the
acquired formula
into the original
OSP task to
reduce search
space
s4
s6
o2
o5
s0
U=1
s6 sj
si
OSP task with
Budget = b
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
U=1
U =2
U=3
U=1
solve reduced task
s3
s4
s6
s7
o1
o2
o4
o5
s0
U=1
Search status snapshot
o6
Value independent
representation
Transform
to:
18. Overview From Private to General Case Empirical Evaluation Future Work
Alleviate the Dependence on Value Non-Negativity
Our work contribution
Best solution
so far
s6
Learned valuable
states DB
New
valuable
state
OSP task with Budget =
b’ < b
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
U=1
U =2
U=3
U=1
OSP task with
Budget = b
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
U=1
U =2
U=3
U=1
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
odummy
G
odummy
odummy
Auxiliary Classical Planning
Problem
Transform
to:
Compile the
acquired formula
into the original
OSP task to
reduce search
space
s4
s6
o2
o5
s0
U=1
s6 sj
si
OSP task with
Budget = b
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
U=1
U =2
U=3
U=1
solve reduced task
s3
s4
s6
s7
o1
o2
o4
o5
s0
U=1
Search status snapshot
o6
Value independent
representation
OSP task with Budget =
b’ < b
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
U=1
U =2
U=3
U=1
solve reduced task
Formula adjustment to wider
range of values
Classical
Planning off-the-
shelf Tool
19. Overview From Private to General Case Empirical Evaluation Future Work
Alleviate the Dependence on Value Non-Negativity
Generate an auxiliary classical planning problem compatible
with the classical planning off-the-shelf tool
Transform
to:
Classical Planning off-the-shelf Tool
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
odummy
G
odummy
odummy
Auxiliary Classical Planning ProblemOSP task with
Budget = b
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
U=1
U =2
U=3
U=1
20. Overview From Private to General Case Empirical Evaluation Future Work
Why Negative Values Effects Need Special Treetment?
Classical planing & non negative OSP
strive to collect the goals (or valuable facts) which are a partial
assignment to state variables
21. Overview From Private to General Case Empirical Evaluation Future Work
Why Negative Values Effects Need Special Treetment?
Generate an auxiliary classical planning problem
s3
s4
s6
s7
o8 s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
odummy
G
odummy
odummy
Auxiliary Classical Planning Problem
OSP task with
Budget = b
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
U=1
U =2
U=3
U=1
22. Overview From Private to General Case Empirical Evaluation Future Work
Why Negative Values Effects Need Special Treetment?
General OSP
take in account the entire state, avoiding collection of facts
carrying negative values
23. Overview From Private to General Case Empirical Evaluation Future Work
Dependency between facts
Consider the following BlocksWorld example
BA
C
BA
C
BA C
Stack(c,b)
Stack(c,a)
Put down(c)
G
U=2
U=2
U=3BA
C
Current State
C
AClear( ) = 1
Clear( ) = 1
Clear( ) = 1
B
24. Overview From Private to General Case Empirical Evaluation Future Work
Dependency between facts
When the focus is on goal or valuable facts, we have 3 goal states
BA
C
BA
C
BA C
Stack(c,b)
Stack(c,a)
Put down(c)
G
U=2
U=2
U=3BA
C
Current State
C
AClear( ) = 1
Clear( ) = 1
Clear( ) = 1
B
ANot Clear( ) = - 2
Not Clear( ) = - 2
Not Clear( ) = - 2
B
C
25. Overview From Private to General Case Empirical Evaluation Future Work
Dependency between facts
When considering a wider set of facts, we stay with one goal state
BA
C
BA
C
BA C
Stack(c,b)
Stack(c,a)
Put down(c)
G
U=0
U=0
U=3BA
C
Current State
C
AClear( ) = 1
Clear( ) = 1
Clear( ) = 1
B
ANot Clear( ) = - 2
Not Clear( ) = - 2
Not Clear( ) = - 2
B
C
26. Overview From Private to General Case Empirical Evaluation Future Work
Ignore Sub Goals Within Negative Context
s3
s4
s6
s7
o8 s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
odummy
G
odummy
odummy
Auxiliary Classical Planning Problem
OSP task with
Budget = b
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
U=1
U =2
U=3
U=1
27. Overview From Private to General Case Empirical Evaluation Future Work
Dependency between states
When the focus is just on target state, we have a goal
Stack(c,a)
G
BA
C
Current State
C
AClear( ) = 10
Clear( ) = 1
Clear( ) = 5
B
BA
C
Current State
U = 6
28. Overview From Private to General Case Empirical Evaluation Future Work
Dependency between states
When we consider also action origin state, it seems to be less
attractive
Stack(c,a)
G
BA
C
Current State
C
AClear( ) = 10
Clear( ) = 1
Clear( ) = 5
B
BA
C
Current State
U = 6U = 11
29. Overview From Private to General Case Empirical Evaluation Future Work
Focus on Actions with Positive Net Values
s3
s4
s6
s7
o8 s9
o3
o6
o1
o2
o4
o5
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
G
odummy
odummy
U(s11 - s8) = -1
U(s6 - s3) = 2
U(s10 – s6) = 1
o13
Auxiliary Classical Planning Problem
OSP task with
Budget = b
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
U=1
U =2
U=3
U=1
30. Overview From Private to General Case Empirical Evaluation Future Work
Utility Function Defenition for General OSP
Definition
For an OSP action o, the total outcome utility of o is
uout
o (o) =
v∈V(eff(o))
uv (eff(o)[v])
31. Overview From Private to General Case Empirical Evaluation Future Work
Utility Function Defenition for General OSP
Definition
For an OSP action o, the total outcome utility of o is
uout
o (o) =
v∈V(eff(o))
uv (eff(o)[v])
Captures fact dependencies
takes in account the entire effect list of an action, rather than
just single facts
32. Overview From Private to General Case Empirical Evaluation Future Work
Utility Function Defenition for General OSP
Definition
For an OSP action o, the net utility of o is
unet
o (o) =
v∈V(eff(o))
[uv (eff(o)[v]) − uv (pre(o)[v])].
33. Overview From Private to General Case Empirical Evaluation Future Work
Utility Function Defenition for General OSP
Definition
For an OSP action o, the net utility of o is
unet
o (o) =
v∈V(eff(o))
[uv (eff(o)[v]) − uv (pre(o)[v])].
Captures state dependencies
traces total benefit of an action with respect to its origin state
in OSP, goal could be achieved just through an action with
total positive net value
34. Overview From Private to General Case Empirical Evaluation Future Work
Different Action Utilities Example
B
A CB A
C
B A
C
B A C
B
A C
-8
-6
-4
-2
0
2
4
6
8
10
12
unstack(c,a) putdown(c) pickup(b) stack (b,c)
outcome utility net utility state utility
state facts utility
clear(a) 2
clear(b) 0
clear(c) -5
not clear(a) 3
not clear(b) -4
not clear(c) 3
on table(a) 1
on table(b) -4
on table(c) 6
on (c,a) 5
on (b,c) -4
handempty 0
not handempty -2
35. Overview From Private to General Case Empirical Evaluation Future Work
Different Perspective - Actions Become The Goal
Lemma
For each π with u(s π ) > 0, there exists a prefix π such that:
1 u(s π ) ≤ u(s π ), and
2 for the last operator olast along π , we have unet
o (olast) > 0.
36. Overview From Private to General Case Empirical Evaluation Future Work
Different Perspective - Actions Become The Goal
Lemma
For each π with u(s π ) > 0, there exists a prefix π such that:
1 u(s π ) ≤ u(s π ), and
2 for the last operator olast along π , we have unet
o (olast) > 0.
The objective
with the net value of an action definition and the lemma in hand,
actions become the goal
37. Overview From Private to General Case Empirical Evaluation Future Work
Different Perspective - Actions Become The Goal
Generate an auxiliary classical planning problem
s3
s4
s6
s7
o8 s9
o3
o6
o1
o2
o4
o5
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
G
odummy
odummy
U(s11 - s8) = -1
U(s6 - s3) = 2
U(s10 – s6) = 1
o13
Auxiliary Classical Planning Problem
OSP task with
Budget = b
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
U=1
U =2
U=3
U=1
38. Overview From Private to General Case Empirical Evaluation Future Work
Different Perspective - Actions Become The Goal
New operator example
goal defined to be vg := 1
put-down(c):
pre:{vc := holding (c), vcc := not clear (c)}
eff:{vc := ontable(c), vcc := clear (c), vg := 1}
39. Overview From Private to General Case Empirical Evaluation Future Work
Implications on Received Formula
Tighter and more accurate formula of actions that must
happen
Transform
to:
Classical Planning off-the-shelf Tool
OSP task with
Budget = b
s3
s4
s6
s7
o8
s9
o3
o6
o1
o2
o4
o5
o13
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
U=1
U =2
U=3
U=1 s3
s4
s6
s7
o8 s9
o3
o6
o1
o2
o4
o5
s5 s11
s12
s10
o9
o10
o11
o12
o14
o7
s8
s0
G
odummy
odummy
U(s11 - s8) = -1
U(s6 - s3) = 2
U(s10 – s6) = 1
o13
Equivalent Classical Planning Problem
40. Overview From Private to General Case Empirical Evaluation Future Work
Implications on Search Space
The formula when the focus is on facts with positive utility
(a1 ∨ a2) ∧ (a3 ∨ a4 ∨ a5 ∨ a6) ∧ (a8 ∨ a9 ∨ a10) ∧ (a12 ∨ a14 ∨ a15)
s1
s2
s5
s6
o8 s10
o4
o4
o1
o2
o6
o5
o12
s4 s14
s15
s11o10
o13s9
s0 s18o16
o10
o13 s16
s7 s12o9 s17
s3 s13o15s8o9
o3
o3
o14
o15
o14
OSP task with
Budget = 4 o11
41. Overview From Private to General Case Empirical Evaluation Future Work
Implications on Search Space
Actions that we aimed to reduced thier cost
(a1 ∨ a2) ∧ (a3 ∨ a4 ∨ a5 ∨ a6) ∧ (a8 ∨ a9 ∨ a10) ∧ (a12 ∨ a14 ∨ a15)
s1
s2
s5
s6
o8 s10
o4
o4
o1
o2
o6
o5
o12
s4 s14
s15
s11o10
o13s9
s0 s18o16
o10
o13 s16
s7 s12o9 s17
s3 s13o15s8o9
o3
o3
o14
o15
o14
OSP task with
Budget = 4
Reduced Budget = 0
o11
42. Overview From Private to General Case Empirical Evaluation Future Work
Implications on Search Space
Secondary effect: more actions with reduced cost
(a1 ∨ a2) ∧ (a3 ∨ a4 ∨ a5 ∨ a6) ∧ (a8 ∨ a9 ∨ a10) ∧ (a12 ∨ a14 ∨ a15)
s1
s2
s5
s6
o8 s10
o4
o4
o1
o2
o6
o5
o12
s4 s14
s15
s11o10
o13s9
s0 s18o16
o10
o13 s16
s7 s12o9 s17
s3 s13o15s8o9
o3
o3
o14
o15
o14
OSP task with
Budget = 4
Reduced Budget = 0
o11
43. Overview From Private to General Case Empirical Evaluation Future Work
Implications on Search Space
Reduced search space
(a1 ∨ a2) ∧ (a3 ∨ a4 ∨ a5 ∨ a6) ∧ (a8 ∨ a9 ∨ a10) ∧ (a12 ∨ a14 ∨ a15)
s1
s2
s5
s6
o8 s10
o4
o4
o1
o2
o6
o5
o12
s4 s14
s15
s11o10
o13s9
s0 s18o16
o10
o13 s16
s7 s12o9 s17
s3 s13o15s8o9
o3
o3
o14
o15
o14
OSP task with
Budget = 4
Reduced Budget = 0
o11
44. Overview From Private to General Case Empirical Evaluation Future Work
Implications on Search Space
Ignore false goals by taking in account net action value
(a1 ∨ a2) ∧ (a3 ∨ a4 ∨ a5 ∨ a6) ∧ (a8 ∨ a9 ∨ a10) ∧ (a12 ∨ a14 ∨ a15)
(a1 ∨ a2) ∧ (a5 ∨ a6) ∧ a8 ∧ a13
s1
s2
s5
s6
o8 s10
o4
o4
o1
o2
o6
o5
o12
s4 s14
s15
s11o10
o13s9
s0 s18o16
o10
o13 s16
s7 s12o9 s17
s3 s13o15s8o9
o3
o3
o14
o15
o14
OSP task with
Budget = 4
Reduced Budget = 0
o11
45. Overview From Private to General Case Empirical Evaluation Future Work
Implications on Search Space
Tight and accuret formula of actions that must happen
(a1 ∨ a2) ∧ (a3 ∨ a4 ∨ a5 ∨ a6) ∧ (a8 ∨ a9 ∨ a10 ∨ a11) ∧ (a14 ∨ a15)
(a1 ∨ a2) ∧ (a5 ∨ a6) ∧ a8 ∧ a13
s1
s2
s5
s6
o8 s10
o4
o4
o1
o2
o6
o5
o12
s4 s14
s15
s11o10
o13s9
s0 s18o16
o10
o13 s16
s7 s12o9 s17
s3 s13o15s8o9
o3
o3
o14
o15
o14
OSP task with
Budget = 4
Reduced Budget = 0
46. Overview From Private to General Case Empirical Evaluation Future Work
Implications on Search Space
Reduce discounted actions = reduce more search space
(a1 ∨ a2) ∧ (a3 ∨ a4 ∨ a5 ∨ a6) ∧ (a8 ∨ a9 ∨ a10 ∨ a11) ∧ (a14 ∨ a15)
(a1 ∨ a2) ∧ (a5 ∨ a6) ∧ a8 ∧ a13
s1
s2
s5
s6
o8 s10
o4
o4
o1
o2
o6
o5
o12
s4 s14
s15
s11o10
o13s9
s0 s18o16
o10
o13 s16
s7 s12o9 s17
s3 s13o15s8o9
o3
o3
o14
o15
o14
OSP task with
Budget = 4
Reduced Budget = 0
47. Overview From Private to General Case Empirical Evaluation Future Work
Action-Oriented vs. Fact-Oriented Goals
Expanded Nodes - Setting u(dom(v)) ∈ {{0}, {1, 2}}
Figure: Empirical results in terms of expanded nodes with different budget restrictions,
where full budget is the minimal cost of achieving maximal utility in a task
48. Overview From Private to General Case Empirical Evaluation Future Work
Action-Oriented vs. Fact-Oriented Goals
Expanded Nodes - Setting u(dom(v)) ∈ {{0}, {1, 2}}
Figure: Empirical results in terms of expanded nodes with different budget restrictions,
where full budget is the minimal cost of achieving maximal utility in a task
49. Overview From Private to General Case Empirical Evaluation Future Work
Action-Oriented vs. Fact-Oriented Goals
Expanded Nodes - Setting u(dom(v)) ∈ {{0}, {0, 1, 2}}
Figure: Empirical results in terms of expanded nodes with different budget restrictions,
where full budget is the minimal cost of achieving maximal utility in a task
50. Overview From Private to General Case Empirical Evaluation Future Work
Action-Oriented vs. Fact-Oriented Goals
Expanded Nodes - Setting u(dom(v)) ∈ {{−1, 0}, {0, 1}}
Figure: Empirical results in terms of expanded nodes with different budget restrictions,
where full budget is the minimal cost of achieving maximal utility in a task
51. Overview From Private to General Case Empirical Evaluation Future Work
Budget Reduction Method Mesure of Quality
Domain Name: OP Fact
blocks 1.79 7.25
depot 30.48 7.00
driverlog 9.88 16.00
grid 90.54 70.60
gripper 4.33 48.00
logistics00 1.07 10.20
logistics98 3.54 2.43
miconic 7.44 14.55
pipesworld-notankage 1571.97 1745.29
pipesworld-tankage 2465.88 3796.00
rovers 10.09 11.85
tpp 2.54 6.32
trucks 62.29 133.00
zenotravel 27.36 50.88
airport 188.67 1028.79
freecell 142.47 1385.30
mystery 246.70 261.59
satellite 9.12 12.00
OVERALL 187.50 344.90
DISCOUNTED ACTIONS PER BUDGET UNIT
52. Overview From Private to General Case Empirical Evaluation Future Work
Empirical Evaluation - Conclusions
Action Oriented Approach
reduction in the number of discounted actions along with an
increase in their diversity
effective in both, general utility functions and non-negative
utility functions
approach effectiveness grows with the increase in subscribed
utilities and budget restrictions
all in all, lower budget, restricted set of preferred actions,
reduced search space
53. Overview From Private to General Case Empirical Evaluation Future Work
Future Work
reduce search space with tighter formula of actions that must
happen
capture more dependencies
focus on group of action reaching the same state
focus on sequence of actions (partial order plans)
recognition of mutually exclusive actions, by preconditions
analysis
L (blind) = O
L(focus on facts)
L(focus on actions)
L(tighter)
We are here
Future
objective
54. Overview From Private to General Case Empirical Evaluation Future Work
References
Mirkis, V. & Domshlak, C. (2014)
Landmarks in Oversubscription Planning
In Proceedings of the 23rd European Conference on Artificial Intelligence
(ECAI), pp. 633–638.
56. Extensions
Handling Actions with Partial Precondition List
The problem
false recognition of actions as goals
redundant cost reduced operators
Solution
operators split compilation
problem structure analysis for inference of mutually exclusive
facts
optimization steps