News
06.02.2023

Schedule for Q&A session and examDear Students, as discussed in the last lecture today, we will have a Q&A session on Monday, 20.02.2023, 10 a.m. Also, as agreed upon earlier, the oneweek takehome exam will cover chapter 5,6 & 7. It will be handed out on Friday, 24.02.2023; the... Read more Dear Students, as discussed in the last lecture today, we will have a Q&A session on Monday, 20.02.2023, 10 a.m. Also, as agreed upon earlier, the oneweek takehome exam will cover chapter 5,6 & 7. It will be handed out on Friday, 24.02.2023; the respective submission is due by Friday, 03.03.2023. Further details will be clarified in and after the Q&A. Best, Sophie 
01.02.2023

Reminder: Exam RegistrationDear Students, please remember to register yourself in the LSF/HISPOS by Wednesday, 08.02.2023, 23:59 if you would like to take the exam. Best, Sophie 
25.01.2023

Ninth AssignmentDear Students, the last book chapter covered this semester is online now. Please submit your summary by Wednesday, 01.02.2023, 10:00 a.m. Best, Sophie 
18.01.2023

Eight AssignmentDear Students, the book chapter on Synchronous Counting is online now. Please submit your summary by next Wednesday, 25.01.2023, 10:00 a.m. Best, Sophie 
07.01.2023

No lecture on MondayDear Students, Unfortunately we have to cancel this Monday's (09.01) lecture. Best, Sophie 
04.01.2023

Seventh ChapterDear Students, the book chapter on SelfStabilising Pulse Synchronisation is online now. The corresponding summary is due on Wednesday, 11.01.2023 10:00 a.m. Best, Sophie 
22.12.2022

Sixth AssignmentDear students, the seventh chapter is online now. The corresponding summary is due by Monday, 02.01.2023 10:00 a.m.
Merry Christmas & a happy New Year!
Best, Sophie 
07.12.2022

Fifth AssignmentDear Students, the rather short sixth chapter on a selfstabilising version of the LynchWelch algorithm is online now. The corresponding summary is due on Wednesday, 14.12.2022, 10:00 a.m. Best, Sophie 
29.11.2022

Fourth AssignmentDear students, the fifth book chapter is available in the materials section. Please submit your summary by Monday, 05.12, 10:00 a.m. Best, Sophie 
16.11.2022

Third AssignmentDear Students, the chapter on lowdegree clock distribution networks is now available in the materials section. Please submit your summary by Wednesday, 23.11, 10:00 a.m. Best, Sophie 
14.11.2022

Sample SummaryDear Students, I uploaded a sample summary of chapter 9, written by a student, which meets what we expect of an excellent submission. Best, Sophie 
08.11.2022

Second AssignmentDear Students, the third book chapter "Synchronising by Approximate Agreement" is available in the materials section. Please submit your summary on your personal CMS status page by Wednesday, 16.11, 10:00 a.m. Best, Sophie 
30.10.2022

ClarificationsDear Students, the definitions missing in Chapter 9 are now available in a separate document in the materials section. Many thanks to the person who pointed out this incompleteness! Apologies and best regards, Sophie 
26.10.2022

Model ChapterDear Students, please take note that I accidentally published the wrong chapter 1 (Models) so please make sure to read the correct updated one! Best, Sophie 
26.10.2022

Reading Material & First SummaryDear Students, the introductory chapter on models is now available in the materials section. You don't need to write a summary of this specific chapter but please read it before the lecture Monday morning.
The first mandatory assignment consists in... Read more Dear Students, the introductory chapter on models is now available in the materials section. You don't need to write a summary of this specific chapter but please read it before the lecture Monday morning.
The first mandatory assignment consists in writing a summary of Chapter 2  Limits of Fault Tolerance. As mentioned earlier, I uploaded a guide on how to write a good summary in the materials section. It is due by Wednesday 02.11, 10:00 a.m.
Feel free to ask questions (by mail!) if there is something unclear!
Best, Sophie 
25.10.2022

First lectureDear Students, the Zoom link is available in the materials section. See you tomorrow! Sophie 
Clock Synchronization and Adversarial Fault Tolerance
People
Lecturers:
 Christoph Lenzen
 Danny Dolev
Teaching Assistant:
 Sophie Wenning
Lecture slots
Weekly lecture slots:
 Monday, 1012
 Wednesday, 1012
First lecture:
 Wednesday, 26.10
There are no tutorials. The lectures are online. The participation link will be sent out to registered students before the first lecture (later registrations are possible; please contact Christoph Lenzen (mail) or Sophie Wenning (mail) for receiving the link in this case).
Content overview
This course takes a close look at how clock synchronization can be achieved in spite of transient and permanent faults, i.e., what happens when one or more clock domains behave in unexpected or even malicious ways. It explores faulttolerant clock distribution protocols, selfstabilising synchronisation algorithms as well as some fundamental limitations resulting from faults. All topics will be first studied through the lense of mathematical proofs. However, as the presented algorithms are simple and practical enough to be implemented on physical chips, we also will investigate realworld constraints arising from hardware and the unforgiving need for efficiency. Based on these observations, we will build bridges back to the theoretical level and try to adapt and improve our models.
Classroom model
This lecture follows the inverted classroom model. This implies that the course is structured as follows:

We will provide you with some reading material one week before each new lecture block and you will prepare a summary of the topic which we will grade. You are also encouraged to ask questions about aspects that you feel you have not yet properly understood. This step is intended to prepare you for the actual lecture.

The lecture itself aims to be interactive. The lecturers will present the topic in more detail. In a subsequent discussion we will answer your questions before moving on to jointly solved exercises designed to further deepen your understanding of the topic.
Prerequisites
No prerequisites beyond basic familiarity with mathematical reasoning are required. It can be helpful to have knowledge about (electric) circuitry and Boolean logic, but this is not mandatory. Note in particular that last semester's course "How to clock your computer" is NOT a prerequisite.
Evaluation
The grades for this course will be computed from:
 Homework assignments (25%): you have to write a short summary for each of the above chapters. These fortnightly assignments will be graded.
 Participation in class (25%): we appreciate your participation in the discussions that will form an important part of each lecture. As your contribution will be graded, attendance at the lectures is strongly recommended.
 Final written submission (50%): a final homework assignment at the end of the semester completes the assessment.