Factorized Scheduling Principle: Learning Interpretable and Transferable Policies via Structured Additive Functions
Authors: Hong Je-Gal, Hyun-Suk Lee
Organizations: Department of Artificial Intelligence and Robotics, Sejong University, South Korea · Artificial Intelligence Robotics Institute (AIRI), Sejong University, South Korea
Scheduling problems arise from repeatedly selecting one item from a set of candidates based on their states. These problems often reduce to assigning priority scores and choosing the highest-ranked item. In this work, we propose a factorized scheduling principle (FSP) framework to learn interpretable and transferable scheduling rules. The FSP framework represents system states as condition distributions and decomposes a global scheduling principle into additive univariate and pairwise components with identifiability constraints. The scheduling principle enables the framework to maintain a simple priority-based structure during deployment. This principle is learned by using a policy-based objective combined with a temporal-difference signal defined on the condition distribution. Experiments on synthetic and realistic scheduling tasks demonstrate the FSP framework's strong performance, interpretability, and zero-shot generalization across different system scales.
Figures & tables
Figure 1 : Illustrative overview of the FSP framework.
Approach
Learned representation
Transferability
Interpretability
Index policies
Analytically defined index
Limited
High
Index learning
Approximated index
Limited
Low–Medium
RL scheduling
Policy or Q(s,a)
No
Low
Structured/Additive RL
Additive policy or value
No
Medium–High
FSP (ours)
Priority principle S(x)
Explicitly considered
High
Table 1 : Comparison of learned representations across scheduling approaches.
Figure 2 : Visual comparison of the component functions of S^ with the true principle S⋆ .
N
Ranking consistency
Avg. reward
Reward gap to oracle
4
0.9940
2.5262
7.9×10−5
8
0.9947
2.7783
1.76×10−4
16
0.9942
2.9377
2.37×10−4
32
0.9941
3.0558
6.15×10−4
Table 2 : Transfer performance with varying N , where S^ is trained with N=8 .
Task
N
FSP
Whittle
NAM
DQN
A2C
PPO
TRPO
QR-DQN
Wireless
10ID
0.109
0.114
0.129
0.112
0.094
0.107
0.112
0.127
5
0.085 ± 0.001
0.096 ± 0.000
0.131 ± 0.000
-0.073 ± 0.002
0.127 ± 0.000
0.129 ± 0.000
0.130 ± 0.000
0.126 ± 0.000
10
0.103 ± 0.001
0.115 ± 0.001
0.109 ± 0.001
-1.313 ± 0.003
0.095 ± 0.001
0.104 ± 0.001
0.112 ± 0.001
0.119 ± 0.001
15
-0.285 ± 0.002
-0.337 ± 0.002
-0.251 ± 0.001
-1.965 ± 0.002
-0.426 ± 0.002
-0.372 ± 0.002
-0.368 ± 0.002
-0.386 ± 0.002
20
-0.781 ± 0.001
-0.888 ± 0.001
-0.752 ± 0.001
-2.609 ± 0.001
-1.045 ± 0.002
-0.971 ± 0.002
-0.951 ± 0.002
-1.019 ± 0.002
Inventory
10ID
-0.353
-0.344
-0.361
-0.355
-0.479
-0.566
-0.566
-0.487
Table 3 : In-distribution reward, 10ID , and out-of-distribution average rewards under varying N and system populations. FSP and Whittle are learned on the 10ID system and transferred without retraining; the other baselines are trained for each N .
Figure 3 : Two of four one-dimensional component functions of the FSP policy in the wireless user scheduling task.
Appendix figures & tables17 assets
Supplementary material from the paper’s appendix.
Appendix
V(sˉt)←Nt1∑n=1NtS(xnt;Θ) and V(sˉt+1)←Nt+11∑n=1Nt+1S(xnt+1;Θ)
Appendix
Algorithm 1 Learning the Global Scheduling Principle S(x)
Figure 4 : The visual comparison of the univariate component functions of S^ with the true principle S⋆ .
Figure 5 : The one-dimensional visual comparison of the pairwise component function of S^ with the true principle S⋆ .
Figure 6 : The two-dimensional visual comparison of the component functions of S^ with the true principle S⋆ .
FSP
Whittle-index policy
Parameter
Value
Parameter
Value
Learning rate ( η )
0.005
State discretization
4×4×4
Basis type
B-spline functions
Discount factor
0.99
1-D basis dimension
30
Dirichlet prior
0.3
2-D basis dimension
15
Value-iteration threshold
10−3
Trade-off hyperparameter ( λ )
0.1
Subsidy-search threshold
5×10−2
Appendix
Table 4 : Hyperparameter summary for FSP and baseline methods.
Parameter
Value
Mean arrival rate ( λn )
0.045
Shape parameter for arrival ( k )
2.0
Capacity scale ( η )
0.6
Throughput weight ( ω )
1.0
Overflow penalty coefficient ( λov )
2.0
Delay penalty coefficient ( λdelay )
1.0
Appendix
Table 5 : System parameters for wireless user scheduling.
Parameter
Value
Replenishment quantity ( Q )
0.5
Demand granularity ( Kd )
50
Mean demand drift std. ( σμ )
0.02
Margin drift std. ( σm )
0.003
Unit cost range ( cn )
[0.02,0.5]
Holding cost range ( hn )
[0.01,0.10]
Appendix
Table 6 : System parameters for inventory replenishment.
Parameter
Value
Global sales capacity ( C )
0.45+0.01⋅N
Inflow rate drift std. ( σρ )
0.01
Margin drift std. ( σm )
0.01
Revenue scaling factor ( α )
5.0
Holding cost ( h )
0.1
Overflow threshold ( τ )
1.0
Appendix
Table 7 : System parameters for warehouse clearance.
N
FSP( 10ID )
DQN( 5ID )
DQN( 10ID )
DQN( 15ID )
DQN( 20ID )
DQN( 10ID , w/o noise)
5ID
0.116
0.127
-
-
-
-
10ID
0.109
-
0.112
-
-
0.122
15ID
-0.266
-
-
-0.297
-
-
20ID
-0.762
-
-
-
-0.855
-
5
0.085 ± 0.001
-0.073 ± 0.002
-
-
-
-
10
0.103 ± 0.001
-
-1.313 ± 0.003
-
-
-1.046 ± 0.001
Appendix
Table 8 : In-distribution rewards and out-of-distribution average rewards of the wireless user scheduling task under varying N with different system populations. (For each N , evaluation is conducted across 100 system instances.)
Figure 7 : One-dimensional component functions of the FSP policy in the wireless user scheduling task.
Figure 8 : Two-dimensional pairwise interaction components of the FSP policy in the wireless user scheduling task.
N
FSP( 10ID )
DQN( 5ID )
DQN( 10ID )
DQN( 15ID )
DQN( 20ID )
DQN( 10ID , w/o noise)
5ID
-0.232
-0.255
-
-
-
-
10ID
-0.353
-
-0.355
-
-
-0.363
15ID
-0.649
-
-
-0.670
-
-
20ID
-0.769
-
-
-
-0.751
-
5
-0.206 ± 0.011
-0.228 ± 0.012
-
-
-
-
10
-0.412 ± 0.008
-
-0.429 ± 0.008
-
-
-0.420 ± 0.008
Appendix
Table 9 : In-distribution rewards and out-of-distribution average rewards of the inventory replenishment task under varying N with different system populations. (For each N , evaluation is conducted across 100 system instances.)
Figure 9 : One-dimensional component functions of the FSP policy in the inventory replenishment environment.
Figure 10 : Learned two-dimensional interaction components ψij in the inventory replenishment environment, visualized as surfaces over the corresponding state dimensions.
N
FSP( 10ID )
DQN( 5ID )
DQN( 10ID )
DQN( 15ID )
DQN( 20ID )
DQN( 10ID , w/o noise)
5ID
0.736
0.772
-
-
-
-
10ID
0.823
-
0.883
-
-
0.881
15ID
0.739
-
-
0.808
-
-
20ID
0.723
-
-
-
0.766
-
5
0.630 ± 0.021
-10.913 ± 1.374
-
-
-
-
10
0.738 ± 0.019
-
-35.238 ± 1.931
-
-
-38.247 ± 2.461
Appendix
Table 10 : In-distribution rewards and out-of-distribution average rewards of the warehouse clearance task under varying N with different system populations. (For each N , evaluation is conducted across 100 system instances.)
Figure 11 : One-dimensional component functions of the FSP policy in the warehouse clearance environment.
Figure 12 : Learned two-dimensional interaction components ψij in the warehouse clearance environment, visualized as surfaces over the corresponding state dimensions.