CMPUT 676: Optimization and Decision-Making under Uncertainty

Fall 2024

Instructor: Xiaoqi Tan (xiaoqi.tan$\textsf{@}$ualberta.ca)
Location & Time: GSB 7-11, MW 12:00 PM – 1:20 PM
Office hour: After class or by appointment


Course Overview

Many real-world problems involve making decisions over time in the presence of various forms of uncertainty. These challenges arise in fields such as Internet advertising, energy sustainability, transportation, financial trading, healthcare, and a wide range of problems in artificial intelligence and machine learning. Although these specific decision problems may initially appear different in various application scenarios, the models and algorithms needed to address them are often similar.

In this research-oriented course, we will review recent developments and discuss open directions in the general field of decision-making under uncertainty through several modern optimization lenses. We will begin with a brief introduction to convex optimization, covering basic concepts of convex sets and convex functions, canonical convex problems, Lagrange multipliers, duality theory, KKT optimality conditions, and standard convex optimization algorithms. Following this, we will explore models and algorithms designed to handle different forms of uncertainty in optimization and decision-making. Major topics include: i) online optimization and competitive analysis; ii) stochastic optimization, learning, and approximation; and iii) algorithmic game theory and mechanism design. These topics are highly interdisciplinary, with strong connections to theoretical computer science, artificial intelligence, machine learning, economics, operations research, statistics, and control. While the course is theoretical in nature, most problems discussed will be motivated and illustrated by practical examples.

Notes: We welcome high level undergrads to audit or take the course (subject to administrative approval).


Course Project

The main assignment of this course is to complete a course project which includes a proposal (20%), an in-class presentation (30%), and a final report (50%).

Proposal (20%): You need to select 1-2 papers from this list and prepare a one-page review (covering the main idea, methodologies, and key results of the selected papers) and a separate one-page proposal (containing potentially multiple ideas, such as improvements, alternative approaches, or new discoveries). Your paper review and proposal will be evaluated using a scoring grid based on the following criteria: i) depth, rigor, and thoroughness of the review, ii) clarity and merit of the proposal, and iii) coherence between the review and the proposal. Please note that the one-page proposal is proportionally more important, which is why the task is titled “Proposal” rather than “Paper Review.”

Presentation (30%): You will give an in-class presentation based on your paper review and proposal. Your presentation will be evaluated using a scoring grid based on the following criteria: i) clarity of the content (e.g., structure of the slides), ii) clarity of the presentation, and iii) effectiveness in addressing questions. These three criteria are equally important in evaluating your presentation.

Final Report (50%): You are expected to complete this course with an 8-10 page final report. As a research-oriented graduate course, it is up to you to decide the focus of your final report—whether it be a proof of a new theorem, a new implementation, or a new survey—but it must be related to your proposal. Your final report will be evaluated using a scoring grid based on the following criteria: i) novelty, ii) consistency with the proposal and presentation, and iii) relevance to this course. Please note that novelty does not necessarily mean novel research results. While you will receive bonus marks for making novel research discoveries relevant to this course, they are not required to receive full marks on the project.


Course Schedule and Readings

Date Topics References and Readings
Sept. 4 Lec 1: Overview
Course topics; Logistics
L1-slides
Convex Optimization (A brief intro)
Sept. 9 Lec 2: Concepts
Convex sets
Convex functions
Convex problems
L2-slides
BV Book: Ch1-Ch4
Sept. 11 Lec 3: Theory
Lagrange multipliers
Duality theory
Optimality conditions
L3-slides
BV Book: Ch5
DB Book
Sept. 16 Lec 4: Algorithms
Gradient descent
Newton’s methods
Barrier methods
Dual ascent
L4-slides
BV Book: Ch9-Ch11
Online Optimization
Sept. 18 Lec 5: Online Algorithms (Basics)
Ski rental problem
Deterministic vs Randomized
Yao’s principle
L5-slides
BP book: Ch1-Ch3
Ski rental
Sept. 23 Lec 6: Online Primal-Dual (OPD)
Time series search
$k$-max and $k$-min search
One-way trading
The OPD approach (1st look)
L6-slides
Online search and one-way trading
$k$-max and $k$-min search
Online selection with convex costs
Sept. 25 Lec 7: Online Knapsack
Threshold-based algorithms
The OPD approach (2nd look)
L7-slides, notes
Online knapsack and variants
Online knapsack with convex costs
Generized one-way trading; multiple knapsack
Knapsack and advice complexity
Sept. 30 No Class (Statutory Holiday)
Oct. 2 Lec 8: Online Matching
RANKING algorithm
The OPD approach (3rd look)
L8-slides
AM Survey, OPD Survey
Readings on RANKING: KVV; An elegant proof;
Economic-based analysis; Randomized OPD analysis
Oct. 7 Lec 9: Online Convex Optimization (OCO)
The Experts problem
OCO: intro + algorithms + variants
Competitive ratio vs. Regret (1st look)
L9-slides
EH Book, CBL Book
Oct. 9 Lec 10: Online Linear Programming (OLP)
OLP: intro + variants
Adversarial inputs vs. Random inputs
Competitive ratio vs. Regret (2nd look)
L10-slides
Random-order models
Online LP under ROM
Online LP under IID
Oct. 14 No Class (Statutory Holiday)
Oct. 16 Lec 11: Beyond Worst-Case Analysis (WCA)
Beyond WCA: why + how
Learning-augmented algorithms
Data-driven algorithms
L11-slides
Beyond WCA
Algorithms with predictions
Data-driven algorithm design
Stochastic Optimization and Learning
Oct. 21 Lec 12: Markov Decision Process (MDP)
MDPs: A brief intro
Algorithms: Value/policy iteration; LP approach
Example: energy storage control
L12-slides
Courses: CMPUT 609, CMPUT 653
Oct. 23 Lec 13: Multi-Armed Bandits (MABs)
MABs: intro + variants
Stochatic bandits; Algorithms
L13-slides
LS Book, BCB Book, Slivkins Book
Oct. 28 Lec 14: Stochastic Approximation
The Robbins-Monro algorithm
Stochastic gradient descent (SGD); Adaptive SGD
Summary: Online vs. Stochastic
L14-slides
Algorithmic Game Theory; Mechanism Design
Oct. 30 Lec 15: Game Theory
Pure-strategy Nash equilibrium
Mixed-strategy Nash equilibrium
L15-slides
Nov. 4 Lec 16: Mechanism Design (MD)
Key concepts of MD
Auctions; Vickrey-Clarke-Groves mechanisms
Optimal auctions
L16-slides
MD reading: Econ, CS
Auctions reading: Survey
Nov. 6 Lec 17: Online Mechanism Design (OMD)
OMD: intro
Online auctions
Posted price mechanisms
Prophet inequalities
Course summary
L17-slides
Nov. 11 No Class (Reading Week Break)
Nov. 13 No Class (Reading Week Break) Proposal Due (eClass link)
Project Presentations
Nov. 18
Nov. 20
Nov. 25
Nov. 27
Dec. 2
Dec. 4
Dec. 9