learning conference reviewer assignments adith swaminathan guide : prof. soumen chakrabarti...
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Learning Conference Reviewer Assignments
Adith Swaminathan
Guide :
Prof. Soumen Chakrabarti
Department of Computer Science andEngineering,Indian Institute of Technology, Bombay
Future Work (from BTP1)
Given WWW2010’s assignments, learn Affinity_Param, Topic_Param and Irritation
Citations as edge featuresLoad-Constrained Partial AssignmentsBetter estimation of Assignment Quality
Background
Conference Reviewer-Paper Assignment as a Many-Many-matching [1]
Minimum Cost Network Flow (MCF)
Conference Reviewer Assignment
Set of Reviewers, R, max #papers = L_i Set of Papers, P, min #reviews = K
Assumption : Only require #reviews, not quality
Suppose we have cost function A_ij(y) for <R_i, P_j>
ILP -> Assumption -> MCF
Two problems
Integer Linear Programs are NP-Hard!– Relax?– More assumptions?
How to determine A_ij?– M * N ~ 10000– Multimodal clues
ILP -> Assumption -> MCF
Enforce structure on A_ij– Better model multimodality– Fewer parameters to fix
“Learn” A_ij using Structured Learning Techniques
A_ij = wT Φ(R_i, P_j, y_ij)
Ramifications of Structured Costs
Costs decompose over <R_i, P_j> pairs– Decomposable Preference Auction– Polynomial Algorithms for DPAs [2]
Restricted notion of optimality– Per-reviewer/Per-paper constraint could be
combinatorial– Stability?
ILP -> Assumption -> MCF
Minimum Cost Network Flow
Directed graph G=(V,E), capacities u(E)>= 0, costs c(E)
Nodes have numbers b(V) : Sum(b(V)) = 0
Task : Find a function f: E->R+ which satisfies the b-flow at minimum cost
Successive Shortest Path Algorithm
Node features and Edge features
Profile
Topics
Reviewer
Topics
Contents
Paper
Affinity
Bid
Topic Overlap
Cites
The Loss Function
L_ij = w_1 * exp(-Affinity_ij) + w_2 * [[1 – Topic_Overlap_ij]] + w_3 * Bid_Cost
Bid_Cost = Potential(R_i, P_j, y_ij)
Irritation (I) and Disappointment (D) needs to be set
Assignment Quality Measures
Number of Bids Violated?– Not a reliable measure.
+ve Bids Violated–ve Bids ViolatedAssignments satisfying Topic MatchConfidence?
Confidence == Quality?
Very sparse– Fewer than 5% observed– Extrapolated Confidence?
Reliable– Bids as a precursor of Confidence [3]
– Confidence-Augmented Loss?
Learning w’s
Transductive Ordinal Regression– Assume : Assignments are independent (Naïve)– Heuristic : Augment observed dataset– Extrapolate observed Confidence [4]
– Learn w over extrapolated dataset
Support Vector Machine for Structured Outputs– Cast as soft-margin SVM formulation [5]
– Upper-bound objective with a convex fn (Optimality?)– Minimize, using Cutting Plane (Approximate)
Transductive Ordinal Regression [6]
SVM Struct. [7]
Loss Augmented Inference ~ Most Violated ConstraintLoss is decomposable -> Modified MCF
PA
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Results
Bimodal Behaviour
•Reviewer either gets few or L_i papers•Load Penalties [8]
•Introduce more parameters•Infer using modified MCF•Learning parameters?
•Load Rebalancing•Tradeoff between MCF optimum and old assignment
Penalise Reviewer Loads
Load Constrained Assignments
Avenues for Future Work
•Document Modelling for Affinity Scores
•Objective Assignment Evaluation
•Transitive Citation Scores
•Load Penalty Parameter Estimation
References
1. The Conference Paper Assignment Problem, J. Goldsmith, R.H. Sloan, 2007
2. MultiAgent Systems: Algorithmic, Game-Theoretic, and Logical Foundations, Y. Shoham, K. Leyton-Brown, 2009
3. Automating the Assignment of Submitted Manuscripts to Reviewers, S.T. Dumais, J. Nielson, 1992
4. Semisupervised Regression with cotraining algorithms, Z. Zhou, M. Li, 2007
References – contd.
5. Learning structured prediction models : A Large Margin Approach, B. Taskar, et al, 2005
6. Ologit : Ordinal Logistic Regression for Zelig, G. King, et al, 2007
7. SVM Learning for Interdependant and Structured Output Spaces, I. Tsochantaridis, et al, 2004
8. Word Alignment via Quadratic Assignment, S. Lacoste-Julien, et al, 2006