15-281, Spring 2025

Artificial Intelligence: Representation and Problem Solving

Overview

Key Information

Monday + Wednesday, 11:00 am - 12:20 pm, Porter Hall 100

Friday afternoon, see Recitations

Shruti Srinivasan (Head TA), Theo Urban (Head TA), Avi Arya, Ethan Mackey, Roy Park
see the 281 Staff page


Grades will be collected in Canvas.
Midterms 15% (each), Final 30%, Programming homework 20%, Written homework 10%, Online homework 5%, Participation 5%

We will use Piazza for questions and any course announcements.

Students will turn in their homework electronically using Gradescope.

This course is about the theory and practice of Artificial Intelligence. We will study modern techniques for computers to represent task-relevant information and make intelligent (i.e., satisfying or optimal) decisions towards the achievement of goals. The search and problem-solving methods are applicable throughout a large range of industrial, civil, medical, financial, robotic, and information systems. We will investigate questions about AI systems such as: how to represent knowledge, how to effectively generate appropriate sequences of actions and how to search among alternatives to find optimal or near-optimal solutions. We will also explore how to deal with uncertainty in the world and how to learn from experience. We will cover the aggregation of conflicting preferences and computational game theory. Throughout the course, we will discuss topics such as AI and Ethics and introduce applications related to AI for Social Good. We expect that by the end of the course students will have a thorough understanding of the algorithmic foundations of AI, how probability and AI are closely interrelated, and how automated agents make decisions. We also expect students to acquire a strong appreciation of the big-picture aspects of developing fully autonomous intelligent agents.

Prerequisites + Corequisites

The prequisites for this course are:

  • 15-122 Principles of Imperative Computation
  • 21-241 Matrices and Linear Transformations
  • 21-127 Concepts of Mathematics or 15-151 Mathematical Foundations of Computer Science.

The corequisite for this course is:

  • 21-122 Integration and Approximation

For this corequisite, you should either have completed it prior to starting 15-281 or have it on your schedule for Fall 2024.

Please see the instructors if you are unsure whether your background is suitable for the course.

Office Hours

We will be using the OHQueue: Link

The calendar of office hours (and recitations) is below.

Schedule (subject to change)

Updated Jan. 11
Dates Topic Reading / Demo Slides
1/13 Mon Introduction AIMA Ch. 1 pptx (pdf)
1/15 Wed Agents and Search AIMA Ch. 3.1-4 pptx (pdf)
1/22 Wed Informed Search AIMA Ch. 3.5-6
1/27 Mon Adversarial Search AIMA Ch. 5
1/29 Wed Constraint Satisfaction Problems AIMA Ch. 6.1-3, 6.5
CSP Demo
2/3 Mon Local Search and Gradient Descent AIMA Ch. 4.1, 6.4
2/5 Wed Linear Programming Boyd and Vandenberghe Ch. 2.2.1, 2.2.4, 4.3-4.3.1
Desmos Demos:
2/10 Mon Integer Programming Desmos Demos: IP
2/12 Wed Propositional Logic and Logical Agents AIMA Ch. 7.1-7
2/17 Mon AI Ethics and Practice Activity
2/19 Wed MIDTERM 1 EXAM In class
2/24 Mon Planning AIMA Ch. 11.1-3, 26.5
2/26 Wed Machine Learning AIMA Ch. 19
3/3 Mon No class: Spring Break
3/5 Wed No class: Spring Break
3/10 Mon Markov Decision Process I AIMA Ch. 17.1-2
3/12 Wed Markov Decision Process II
3/17 Mon Reinforcement Learning I AIMA Ch. 22.1-3
3/19 Wed Reinforcement Learning II AIMA Ch. 22.4-4.3
3/24 Mon Bayes Nets: Representation AIMA Ch. 12.1-5, 13.1-2
Bayes Net Demo (highres)
3/26 Wed MIDTERM 2 EXAM In class
3/31 Mon Bayes Nets: Independence AIMA Ch. 12.4-5, 13.2
4/2 Wed Bayes Nets: Inference AIMA Ch. 13.3
4/7 Mon Bayes Nets: Sampling AIMA Ch. 13.4
Likelihood Demo, Gibbs Demo
4/9 Wed Hidden Markov Models AIMA Ch. 14.1-3
4/14 Mon Particle Filtering AIMA Ch. 14.5
4/16 Wed Game Theory: Equilibrium AIMA Ch. 18.1-2
4/21 Mon Game Theory: Social Choice AIMA Ch. 17.6
4/23 Wed Ask Me Anything
TBD FINAL EXAM, Time + location TBD

Recitations

Recitations start the first week of class, Friday, Jan 17. Recitation attendence is required , as past semesters have found it a critical part of success in the class. Also, the recitation materials published below are required content and are in-scope for midterm and final exams. Recitation attendance will be combined with poll responses to compute your overall participation grade.

Recitation section assignments will be locked-down after the third week. Until then, you may try attending different recitation sections to find the best fit for you. In the case of any over-crowded recitation sections, priority goes to students that are officially registered for that section in SIO. The process to select your final recitation assignment will be announced on the course Q-and-A as we get closer to Recitation 4, Feb. 7.

Time Location Section TAs Resources
Fri, 12:00 - 12:50 pm PH A18A A Ethan and Shruti Section A Resources
Fri, 1:00 - 1:50 pm PH 125B B Avi and Theo Section B Resources
Fri, 1:00 - 1:50 pm PH A22 C Roy and Shruti Section C Resources
Fri, 2:00 - 2:50 pm WEH 5320 D Ethan and Roy Section D Resources
Fri, 2:00 - 2:50 pm WEH 8427 E Avi and Theo Section E Resources
Dates Recitation Handouts
1/17 Fri Recitation 1 pdf (sol)

nim.zip
1/24 Fri Recitation 2
1/31 Fri Recitation 3
2/7 Fri Recitation 4
2/14 Fri Recitation 5
2/21 Fri Recitation 6
2/28 Fri Recitation 7
3/7 Fri No Recitation: Spring Break
3/14 Fri Recitation 8
3/21 Fri Recitation 9
3/28 Fri Recitation 10
4/4 Fri No Recitation: Spring Carnival
4/11 Fri Recitation 11
11/29 Fri Recitation 12
12/6 Fri Recitation 14

Exams

The course includes two midterm exams and a final exam. The midterms will take place in lecture. The final exam date and location are TBD. Plan any travel around exams, as exams will not be rescheduled.

Assignments

There will be five programming assignments and eleven written/online assignments (subject to change). Written/online assignments will involve working through algorithms presented in the class, deriving and proving mathematical results, and critically analyzing material presented in class. Programming assignments will involve writing code in Python to implement various algorithms.

For any assignments that aren't released yet, the dates below are tentative and subject to change.

Assignment due dates (Due at 11:59 PM unless otherwise specified)

Assignment Link (if released) Due Date
P0 P0: Tutorial (required, worth zero points) 1/23/2025
HW1 (online) Online 1/23/2025
HW2 (online, written) Released TBD 1/30/2025
P1 Released TBD 2/6/2025
HW3 (online) Released TBD 2/6/2025
HW4 (online, written) Released TBD 2/13/2025
P2 Released TBD 2/20/2025
HW5 (online, written) Released TBD 2/20/2025
P3 Released TBD 2/27/2025
HW6 (online) Released TBD 3/20/2025
HW7 (online, written) Released TBD 3/27/2025
P4 Released TBD 3/31/2025
HW8 (online) Released TBD 4/3/2025
HW9 (online, written) Released TBD 4/10/2025
HW 10 (online, written) Released TBD 4/17/2025
P5 Released TBD 4/24/2025
HW11 (online) Released TBD 4/24/2025

Course Notes

Below are course notes developed by the course staff over the years.

Topic Link (if released)
Search Search Notes
CSPs
Local Search
Linear and Integer Programming
Propositional Logic and Logical Agents
Classical Planning
Markov Decision Process
Reinforcement Learning
Probability
Bayes Nets
HMMs and Particle Filters
Game Theory

Policies

Grading

Grades will be collected and reported in Canvas. Please let us know if you believe there to be an error the grade reported in Canvas.

Final scores will be composed of:

  • 15% Midterm exams (each)
  • 30% Final exam
  • 20% Programming homework
  • 10% Written homework
  • 5% Online homework
  • 5% Participation

Final Grade

This class is not curved. However, we convert final course scores to letter grades based on grade boundaries that are determined at the end of the semester. What follows is a rough guide to how course grades will be established, not a precise formula — we will fine-tune cutoffs and other details as we see fit after the end of the course. This is meant to help you set expectations and take action if your trajectory in the class does not take you to the grade you are hoping for. So, here's a rough heuristics about the correlation between final grades and total scores:

  • A: above 90%
  • B: 80-90%
  • C: 70-80%
  • D: 60-70%

This heuristic assumes that the makeup of a student's grade is not wildly anomalous: exceptionally low overall scores on exams, programming assignments, or written assignments will be treated on a case-by-case basis and, while rare, could potentially drop a students grade.

Precise grade cutoffs will not be discussed at any point during or after the semester.

Participation

In class, we will use a series of polls as part of an active learning technique called Peer Instruction. Your participation grade will be based on the percentage of these in-class poll questions answered, as well as the number of recitations you attend:

  • 0% for 50% or less
  • 5% for 80% or greater poll participation + recitation attendance
  • Linear scale for values in between 50% and 80%
  • Correctness of in-class polling responses will not be taken into account for participation grades.
  • If you have systemic/repeated technical issues, please let us know as soon as possible, so we can resolve the situation.
  • Missing polls or recitations due to absences (e.g., brief illness) or due to technical difficulties is expected occasionally, and this is why you only need to answer >= 80% of the polls to get full credit.

It is against the course academic integrity policy to answer in-class polls when you are not present in lecture. Violations of this policy will be reported as an academic integrity violation. Information about academic integrity at CMU may be found at https://www.cmu.edu/academic-integrity.

Late Policy

Programming assignments, written homework, and online homework:

  • 6 slip days across all assignment types
  • Use up to two per assignment
  • Slip days are counted in full 24-hour increments from the assignment deadline. No fractions of a slip day are used
  • When multiple assignments are due on the same day, they are treated as a single assignment for slip day purposes
    • For example, if P0 and HW1 are due on the same day and you turn in P0 one day late and HW1 two days late, you will have used only two slip days (not three)
  • You may use these at your discretion, but they are intended for minor illness and other disruptive events outside of your control, and not for poor time management
  • No need to inform us that you are using a slip day; just submit it to Gradescope during the slip day
  • You are responsible to keep track of your own slip days. Gradescope will not enforce the total number of slip days

Aside from this, there will be no extensions on assignments in general. If you think you really really need an extension on a particular assignment, contact the instructor as soon as possible and before the deadline. Please be aware that extensions are entirely discretionary and will be granted only in exceptional circumstances outside of your control (e.g., due to severe illness or major personal/family emergencies, but not for competitions, club-related events or interviews). The instructors will require confirmation from your academic advisor, as appropriate.
Nearly all situations that make you run late on an assignment homework can be avoided with proper planning, often just starting early. Here are some examples:

  • I have so many deadlines this week: you know your deadlines ahead of time, so plan accordingly.
  • It's a minute before the deadline and the network is down: you always have multiple submissions -- it's not a good idea to wait for the deadline for your first submission.
  • My computer crashed and I lost everything: Use Dropbox or similar to do real-time backup -- recover your files onto AFS and finish your homework from a cluster machine.
  • My fraternity/sorority/club has that big event that is taking all my time: Schedule your extra-curricular activities around your classes, not vice versa.

Again, you should be keeping track of how many slip days you have used, and ensure that you are both using no more than 2 slip days per assignment and using no more than 6 slip days in the semester. If you submit an assignment late but do not have enough slip days to use for either reason, one of two things will happen:

  • If you submitted a version of the assignment on time or within your available slip days, we will grade the last valid assignment submission
  • If you did not submit a version on time, you will receive a 0

You are encouraged to submit a version of your assignment early. It is not a good idea to wait for the deadline for your first submission.

Collaboration Policy

We encourage you to discuss course content and assignments with your classmates. However, these discussion must be kept at a conceptual level only.

  • You may NOT view, share, or communicate about any artifact that will be submitted as part of an assignment. Example artifacts include, but are not limited to: code, pseudocode, diagrams, and text.
  • You may look at another student's Python error messages and discuss what the error means at a conceptual level. However, you may NOT give specific instructions to fix the error.
  • All work that you present must be your own. Thus, generative AI tools may not be used to generate any part of your assignment submission. (Yes, these tools are awesome, but we've designed this course to minimize the amount of code/material that you need to write, so you should be able to complete the assignments in a timely manner without these aids.)
  • If you discuss material in a homework at a high level with a peer, you must wait at least 1 hour before writing the homework.
  • Using any external sources of code or algorithms in any way must have approval from the instructor before submitting the work. For example, you must get instructor approval before using an algorithm you found online for implementing a heuristic function in a programming assignment. The following are pre-approved exceptions:
    • Code provided by the course staff or materials, including code from the textbook
    • Documentation for permitted Python libraries

Programming Assignment Partners

The only exception to the above collaboration policy is when you share programming code directly with your programming assignment partner.

  • You are allowed to work in groups of at most two on each programming assignment, i.e. you and one partner
  • You must specify your partner when you submit each assignment
  • Once you start working with a partner on an assignment, you may not switch to another partner for that assignment
  • You may change partners between assignments. In fact, you are strongly encouraged to change partners occasionally
  • Important: You are responsible for making sure that both you AND your partner understand the work that you submit. If we discover that one partner cannot answer basic questions about the submitted work, both students in the group will be reported for an academic integrity violation.

Violations of these policies will be reported as an academic integrity violation. Information about academic integrity at CMU may be found at https://www.cmu.edu/academic-integrity. Please contact the instructor if you ever have any questions regarding academic integrity or these collaboration policies.

Accommodations for Students with Disabilities

If you have a disability and have an accommodations letter from the Disability Resources office, we encourage you to discuss your accommodations and needs with us as early in the semester as possible. We will work with you to ensure that accommodations are provided as appropriate. If you suspect that you may have a disability and would benefit from accommodations but are not yet registered with the Office of Disability Resources, we encourage you to visit their website.

Statement of Support for Students Health & Well-being

Take care of yourself. Do your best to maintain a healthy lifestyle this semester by eating well, exercising, getting enough sleep, and taking some time to relax. This will help you achieve your goals and cope with stress.
All of us benefit from support during times of struggle. There are many helpful resources available on campus and an important part of the college experience is learning how to ask for help. Asking for support sooner rather than later is almost always helpful.
If you or anyone you know experiences any academic stress, difficult life events, or feelings like anxiety or depression, we strongly encourage you to seek support. Counseling and Psychological Services (CaPS) is here to help: call 412-268-2922 and visit their website at http://www.cmu.edu/counseling/. Consider reaching out to a friend, faculty or family member you trust for help getting connected to the support that can help.
If you have questions about this or your coursework, please let us know. Thank you, and have a great semester.

Statement of Commitment to a Diverse Learning Environment

We must treat every individual with respect. We are diverse in many ways, and this diversity is fundamental to building and maintaining an equitable and inclusive campus community. Diversity can refer to multiple ways that we identify ourselves, including but not limited to race, color, national origin, language, sex, disability, age, sexual orientation, gender identity, religion, creed, ancestry, belief, veteran status, or genetic information. Each of these diverse identities, along with many others not mentioned here, shape the perspectives our students, faculty, and staff bring to our campus. We, at CMU, will work to promote diversity, equity and inclusion not only because diversity fuels excellence and innovation, but because we want to pursue justice. We acknowledge our imperfections while we also fully commit to the work, inside and outside of our classrooms, of building and sustaining a campus community that increasingly embraces these core values.

Each of us is responsible for creating a safer, more inclusive environment.

Unfortunately, incidents of bias or discrimination do occur, whether intentional or unintentional. They contribute to creating an unwelcoming environment for individuals and groups at the university. Therefore, the university encourages anyone who experiences or observes unfair or hostile treatment on the basis of identity to speak out for justice and support, within the moment of the incident or after the incident has passed. Anyone can share these experiences using the following resources:
  • Center for Student Diversity and Inclusion: csdi@andrew.cmu.edu, (412) 268-2150
  • Report-It online anonymous reporting platform: reportit.net username: tartans password: plaid
All reports will be documented and deliberated to determine if there should be any following actions. Regardless of incident type, the university will use all shared experiences to transform our campus climate to be more equitable and just.